元素を英語で覚えよう!

化学

Periodic Table

Hydrogen

Discovered State
1766 Gas
Atomic Mass Density
1.008 0.08988 g/L
1 1 H 2
Electrons Protons Neutrons
1 1 0
Electronic Configuration
1s1
  • Discovered By: Henry Cavendish
  • Appearance: colorless gas
  • Category: diatomic nonmetal
  • Melting Point: 13.99 K
  • Boiling Point: 20.271 K
  • Ox. State: -1, 1
  • Bonding Type: diatomic
  • Electronegativity: 2.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.

Helium

Discovered State
1895 Gas
Atomic Mass Density
4.0026022 0.1786 g/L
4 2 He
Electrons Protons Neutrons
2 2 2
Electronic Configuration
1s2
  • Discovered By: Pierre Janssen
  • Appearance: colorless gas
  • Category: noble gas
  • Melting Point: 0.95 K
  • Boiling Point: 4.222 K
  • Ox. State:
  • Bonding Type: atomic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among all the elements.

Lithium

Discovered State
1817 Solid
Atomic Mass Density
6.94 0.534 g/L
7 3 Li
Electrons Protons Neutrons
3 3 4
Electronic Configuration
[He] 2s1
  • Discovered By: Johan August Arfwedson
  • Appearance: silvery-white
  • Category: alkali metal
  • Melting Point: 453.65 K
  • Boiling Point: 1615 K
  • Ox. State: 1
  • Bonding Type: metallic
  • Electronegativity: 0.98
  • Wiki Link: Source Link
  • Element Image: Image Link

Lithium (from Greek:λίθος lithos, "stone") is a chemical element with the symbol Li and atomic number 3. It is a soft, silver-white metal belonging to the alkali metal group of chemical elements. Under standard conditions it is the lightest metal and the least dense solid element.

Beryllium

Discovered State
1798 Solid
Atomic Mass Density
9.01218315 1.848 g/L
9 4 Be
Electrons Protons Neutrons
4 4 5
Electronic Configuration
[He] 2s2
  • Discovered By: Louis Nicolas Vauquelin
  • Appearance: white-gray
  • Category: alkaline earth metal
  • Melting Point: 1560 K
  • Boiling Point: 2743 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity: 1.57
  • Wiki Link: Source Link
  • Element Image: Image Link

Beryllium is a chemical element with symbol Be and atomic number 4. It is created through stellar nucleosynthesis and is a relatively rare element in the universe. It is a divalent element which occurs naturally only in combination with other elements in minerals.

Boron

Discovered State
1807 Solid
Atomic Mass Density
10.81 2.46 g/L
10 5 B
Electrons Protons Neutrons
5 5 5
Electronic Configuration
[He] 2s22p1
  • Discovered By: Joseph Louis Gay-Lussac
  • Appearance: black-brown
  • Category: metalloid
  • Melting Point: 2348 K
  • Boiling Point: 4273 K
  • Ox. State: 1, 2, 3
  • Bonding Type: covalent network
  • Electronegativity: 2.04
  • Wiki Link: Source Link
  • Element Image: Image Link

Boron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.

Carbon

Discovered State
Ancient Solid
Atomic Mass Density
12.011 2.26 g/L
12 6 C
Electrons Protons Neutrons
6 6 6
Electronic Configuration
[He] 2s22p2
  • Discovered By: Ancient Egypt
  • Appearance: black
  • Category: polyatomic nonmetal
  • Melting Point: 3823 K
  • Boiling Point: 4300 K
  • Ox. State: -4, -3, -2, -1, 1, 2, 3, 4
  • Bonding Type: covalent network
  • Electronegativity: 2.55
  • Wiki Link: Source Link
  • Element Image: Image Link

Carbon (from Latin:carbo "coal") is a chemical element with symbol C and atomic number 6. On the periodic table, it is the first (row 2) of six elements in column (group) 14, which have in common the composition of their outer electron shell. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds.

Nitrogen

Discovered State
1772 Gas
Atomic Mass Density
14.0067 0.001251 g/L
14 7 N 2
Electrons Protons Neutrons
7 7 7
Electronic Configuration
[He] 2s22p3
  • Discovered By: Daniel Rutherford
  • Appearance: colorless gas
  • Category: diatomic nonmetal
  • Melting Point: 63 K
  • Boiling Point: 77 K
  • Ox. State: -3, -2, -1, 1, 2, 3, 4, 5
  • Bonding Type: diatomic
  • Electronegativity: 3.04
  • Wiki Link: Source Link
  • Element Image: Image Link

Nitrogen is a chemical element with symbol N and atomic number 7. It is the lightest pnictogen and at room temperature, it is a transparent, odorless diatomic gas. Nitrogen is a common element in the universe, estimated at about seventh in total abundance in the Milky Way and the Solar System.

Oxygen

Discovered State
1774 Gas
Atomic Mass Density
15.9994 1.429 g/L
16 8 O 2
Electrons Protons Neutrons
8 8 8
Electronic Configuration
[He] 2s22p4
  • Discovered By: Carl Wilhelm Scheele
  • Appearance: colorless gas
  • Category: diatomic nonmetal
  • Melting Point: 54.36 K
  • Boiling Point: 90.188 K
  • Ox. State: -2, -1, 1, 2
  • Bonding Type: diatomic
  • Electronegativity: 3.44
  • Wiki Link: Source Link
  • Element Image: Image Link

Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms compounds (notably oxides) with most elements. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.

Fluorine

Discovered State
1670 Gas
Atomic Mass Density
18.998 1.696 g/L
19 9 F
Electrons Protons Neutrons
9 9 10
Electronic Configuration
[He] 2s22p5
  • Discovered By: André-Marie Ampère
  • Appearance:
  • Category: diatomic nonmetal
  • Melting Point: 53.48 K
  • Boiling Point: 85.03 K
  • Ox. State: -1
  • Bonding Type: atomic
  • Electronegativity: 3.98
  • Wiki Link: Source Link
  • Element Image: Image Link

Fluorine is a chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive:almost all other elements, including some noble gases, form compounds with fluorine.

Neon

Discovered State
1898 Gas
Atomic Mass Density
20.17976 0.9002 g/L
20 10 Ne
Electrons Protons Neutrons
10 10 10
Electronic Configuration
[He] 2s22p6
  • Discovered By: Morris Travers
  • Appearance: colorless gas
  • Category: noble gas
  • Melting Point: 24.56 K
  • Boiling Point: 27.104 K
  • Ox. State:
  • Bonding Type: atomic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Neon is a chemical element with symbol Ne and atomic number 10. It is in group 18 (noble gases) of the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air.

Sodium

Discovered State
1807 solid
Atomic Mass Density
22.989 0.968 g/L
23 11 Na
Electrons Protons Neutrons
11 11 12
Electronic Configuration
[Ne] 3s1
  • Discovered By: Humphry Davy
  • Appearance: silvery white metallic
  • Category: alkali metal
  • Melting Point: 370.944 K
  • Boiling Point: 1156.09 K
  • Ox. State: -1, 1
  • Bonding Type: metallic
  • Electronegativity: 0.93
  • Wiki Link: Source Link
  • Element Image: Image Link

Sodium /ˈsoʊdiəm/ is a chemical element with symbol Na (from Ancient Greek Νάτριο) and atomic number 11. It is a soft, silver-white, highly reactive metal. In the Periodic table it is in column 1 (alkali metals), and shares with the other six elements in that column that it has a single electron in its outer shell, which it readily donates, creating a positively charged atom - a cation.

Magnesium

Discovered State
1808 solid
Atomic Mass Density
24.305 1.738 g/L
24 12 Mg
Electrons Protons Neutrons
12 12 12
Electronic Configuration
[Ne] 3s2
  • Discovered By: Joseph Black
  • Appearance: shiny grey solid
  • Category: alkaline earth metal
  • Melting Point: 923 K
  • Boiling Point: 1363 K
  • Ox. State: 1, 2
  • Bonding Type: metallic
  • Electronegativity: 1.31
  • Wiki Link: Source Link
  • Element Image: Image Link

Magnesium is a chemical element with symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (Group 2, or alkaline earth metals) of the periodic table:they each have the same electron configuration in their outer electron shell producing a similar crystal structure. Magnesium is the ninth most abundant element in the universe.

Aluminium

Discovered State
Ancient solid
Atomic Mass Density
26.98153857 2.7 g/L
27 13 Al
Electrons Protons Neutrons
13 13 14
Electronic Configuration
[Ne] 3s23p1
  • Discovered By: Humphry Davy
  • Appearance: silvery gray metallic
  • Category: post-transition metal
  • Melting Point: 933.47 K
  • Boiling Point: 2743 K
  • Ox. State: 1, 3
  • Bonding Type: metallic
  • Electronegativity: 1.61
  • Wiki Link: Source Link
  • Element Image: Image Link

Aluminium (or aluminum; see different endings) is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal. Aluminium is the third most abundant element (after oxygen and silicon), and the most abundant metal, in the Earth's crust.

Silicon

Discovered State
1854 solid
Atomic Mass Density
28.085 2.329 g/L
28 14 Si
Electrons Protons Neutrons
14 14 14
Electronic Configuration
[Ne] 3s23p2
  • Discovered By: Jöns Jacob Berzelius
  • Appearance: crystalline
  • Category: metalloid
  • Melting Point: 1687 K
  • Boiling Point: 3538 K
  • Ox. State: -4, -3, -2, -1, 1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.9
  • Wiki Link: Source Link
  • Element Image: Image Link

Silicon is a chemical element with symbol Si and atomic number 14. It is a tetravalent metalloid, more reactive than germanium, the metalloid directly below it in the table. Controversy about silicon's character dates to its discovery.

Phosphorus

Discovered State
1669 solid
Atomic Mass Density
30.9737619985 1.823 g/L
31 15 P
Electrons Protons Neutrons
15 15 16
Electronic Configuration
[Ne] 3s23p3
  • Discovered By: Hennig Brand
  • Appearance: colourless
  • Category: polyatomic nonmetal
  • Melting Point: 317 K
  • Boiling Point: 554 K
  • Ox. State: -3, -2, -1, 1, 2, 3, 4, 5
  • Bonding Type: covalent network
  • Electronegativity: 2.19
  • Wiki Link: Source Link
  • Element Image: Image Link

Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but due to its high reactivity, phosphorus is never found as a free element on Earth. Instead phosphorus-containing minerals are almost always present in their maximally oxidised state, as inorganic phosphate rocks.

Sulfur

Discovered State
Ancient solid
Atomic Mass Density
32.06 2.07 g/L
32 16 S
Electrons Protons Neutrons
16 16 16
Electronic Configuration
[Ne] 3s23p4
  • Discovered By: Ancient china
  • Appearance: lemon yellow
  • Category: polyatomic nonmetal
  • Melting Point: 388.36 K
  • Boiling Point: 717.8 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: covalent network
  • Electronegativity: 2.58
  • Wiki Link: Source Link
  • Element Image: Image Link

Sulfur or sulphur (see spelling differences) is a chemical element with symbol S and atomic number 16. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8.

Chlorine

Discovered State
1774 Gas
Atomic Mass Density
35.45 3.2 g/L
35 17 Cl
Electrons Protons Neutrons
17 17 18
Electronic Configuration
[Ne] 3s23p5
  • Discovered By: Carl Wilhelm Scheele
  • Appearance: pale yellow-green gas
  • Category: diatomic nonmetal
  • Melting Point: 171.6 K
  • Boiling Point: 239.11 K
  • Ox. State: -1, 1, 2, 3, 4, 5, 6, 7
  • Bonding Type: covalent network
  • Electronegativity: 3.16
  • Wiki Link: Source Link
  • Element Image: Image Link

Chlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.

Argon

Discovered State
1894 Gas
Atomic Mass Density
39.9481 1.784 g/L
40 18 Ar
Electrons Protons Neutrons
18 18 22
Electronic Configuration
[Ne] 3s23p6
  • Discovered By: Lord Rayleigh
  • Appearance: colorless gas
  • Category: noble gas
  • Melting Point: 83.81 K
  • Boiling Point: 87.302 K
  • Ox. State:
  • Bonding Type: atomic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Argon is a chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most common gas in the Earth's atmosphere, at 0.934% (9,340 ppmv), making it over twice as abundant as the next most common atmospheric gas, water vapor (which averages about 4000 ppmv, but varies greatly), and 23 times as abundant as the next most common non-condensing atmospheric gas, carbon dioxide (400 ppmv), and more than 500 times as abundant as the next most common noble gas, neon (18 ppmv).

Potassium

Discovered State
1807 Solid
Atomic Mass Density
39.09831 0.862 g/L
39 19 K
Electrons Protons Neutrons
19 19 20
Electronic Configuration
[Ar] 4s1
  • Discovered By: Humphry Davy
  • Appearance: silvery gray
  • Category: alkali metal
  • Melting Point: 336.7 K
  • Boiling Point: 1032 K
  • Ox. State: 1
  • Bonding Type: metallic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name is derived. In the Periodic table, potassium is one of seven elements in column (group) 1 (alkali metals):they all have a single valence electron in their outer electron shell, which they readily give up to create an atom with a positive charge - a cation, and combine with anions to form salts.

Calcium

Discovered State
1808 Solid
Atomic Mass Density
40.0784 1.55 g/L
40 20 Ca
Electrons Protons Neutrons
20 20 20
Electronic Configuration
[Ar] 4s2
  • Discovered By: Humphry Davy
  • Appearance:
  • Category: alkaline earth metal
  • Melting Point: 1115 K
  • Boiling Point: 1757 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.

Scandium

Discovered State
1876 Solid
Atomic Mass Density
44.9559085 2.985 g/L
45 21 Sc
Electrons Protons Neutrons
21 21 24
Electronic Configuration
[Ar] 3d14s2
  • Discovered By: Lars Fredrik Nilson
  • Appearance: silvery white
  • Category: transition metal
  • Melting Point: 1814 K
  • Boiling Point: 3109 K
  • Ox. State: 1, 2, 3
  • Bonding Type: metallic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Scandium is a chemical element with symbol Sc and atomic number 21. A silvery-white metallic d-block element, it has historically been sometimes classified as a rare earth element, together with yttrium and the lanthanoids. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia.

Titanium

Discovered State
1791 Solid
Atomic Mass Density
44.9559085 4.506 g/L
48 22 Ti
Electrons Protons Neutrons
22 22 26
Electronic Configuration
[Ar] 3d24s2
  • Discovered By: William Gregor
  • Appearance: silvery grey
  • Category: transition metal
  • Melting Point: 1941 K
  • Boiling Point: 3560 K
  • Ox. State: -1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.54
  • Wiki Link: Source Link
  • Element Image: Image Link

Titanium is a chemical element with symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density and high strength. It is highly resistant to corrosion in sea water, aqua regia and chlorine.

Vanadium

Discovered State
1803 Solid
Atomic Mass Density
50.94151 6 g/L
51 23 V
Electrons Protons Neutrons
23 23 28
Electronic Configuration
[Ar] 3d34s2
  • Discovered By: Andrés Manuel del Río
  • Appearance: blue-silver-grey metal
  • Category: transition metal
  • Melting Point: 2183 K
  • Boiling Point: 3680 K
  • Ox. State: -1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.63
  • Wiki Link: Source Link
  • Element Image: Image Link

Vanadium is a chemical element with symbol V and atomic number 23. It is a hard, silvery grey, ductile and malleable transition metal. The element is found only in chemically combined form in nature, but once isolated artificially, the formation of an oxide layer stabilizes the free metal somewhat against further oxidation.

Chromium

Discovered State
1798 Solid
Atomic Mass Density
51.99616 7.19 g/L
52 24 Cr
Electrons Protons Neutrons
24 24 28
Electronic Configuration
[Ar] 3d54s1
  • Discovered By: Louis Nicolas Vauquelin
  • Appearance: silvery metallic
  • Category: transition metal
  • Melting Point: 2180 K
  • Boiling Point: 2944 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 1.63
  • Wiki Link: Source Link
  • Element Image: Image Link

Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.

Manganese

Discovered State
1774 Solid
Atomic Mass Density
54.9380443 7.21 g/L
55 25 Mn
Electrons Protons Neutrons
25 25 30
Electronic Configuration
[Ar] 3d54s2
  • Discovered By: Torbern Olof Bergman
  • Appearance: silvery metallic
  • Category: transition metal
  • Melting Point: 1519 K
  • Boiling Point: 2334 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 1.55
  • Wiki Link: Source Link
  • Element Image: Image Link

Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in combination with iron, and in many minerals. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels.

Iron

Discovered State
Ancient Solid
Atomic Mass Density
55.8452 7.874 g/L
56 26 Fe
Electrons Protons Neutrons
26 26 30
Electronic Configuration
[Ar] 3d64s2
  • Discovered By: 5000 BC
  • Appearance: lustrous metallic with a grayish tinge
  • Category: transition metal
  • Melting Point: 1811 K
  • Boiling Point: 3134 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 1.83
  • Wiki Link: Source Link
  • Element Image: Image Link

Iron is a chemical element with symbol Fe (from Latin:ferrum) and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core.

Cobalt

Discovered State
Ancient Solid
Atomic Mass Density
58.9331944 8.9 g/L
59 27 Co
Electrons Protons Neutrons
27 27 32
Electronic Configuration
[Ar] 3d74s2
  • Discovered By: Georg Brandt
  • Appearance: hard lustrous gray metal
  • Category: transition metal
  • Melting Point: 1768 K
  • Boiling Point: 3200 K
  • Ox. State: -1, 1, 2, 3, 4, 5
  • Bonding Type: metallic
  • Electronegativity: 1.88
  • Wiki Link: Source Link
  • Element Image: Image Link

Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.

Nickel

Discovered State
1751 Solid
Atomic Mass Density
58.69344 8.908 g/L
58 28 Ni
Electrons Protons Neutrons
28 28 30
Electronic Configuration
[Ar] 3d84s2
  • Discovered By: Axel Fredrik Cronstedt
  • Appearance: lustrous, metallic, and silver with a gold tinge
  • Category: transition metal
  • Melting Point: 1728 K
  • Boiling Point: 3003 K
  • Ox. State: -1, 1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.91
  • Wiki Link: Source Link
  • Element Image: Image Link

Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile.

Copper

Discovered State
Ancient Solid
Atomic Mass Density
63.5463 8.96 g/L
64 29 Cu
Electrons Protons Neutrons
29 29 35
Electronic Configuration
[Ar] 3d104s1
  • Discovered By: Middle East
  • Appearance: red-orange metallic luster
  • Category: transition metal
  • Melting Point: 1357.77 K
  • Boiling Point: 2835 K
  • Ox. State: 1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.9
  • Wiki Link: Source Link
  • Element Image: Image Link

Copper is a chemical element with symbol Cu (from Latin:cuprum) and atomic number 29. It is a soft, malleable and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a reddish-orange color.

Zinc

Discovered State
1746 Solid
Atomic Mass Density
65.382 7.14 g/L
65 30 Zn
Electrons Protons Neutrons
30 30 35
Electronic Configuration
[Ar] 3d104s2
  • Discovered By: India
  • Appearance: silver-gray
  • Category: transition metal
  • Melting Point: 692.68 K
  • Boiling Point: 1180 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity: 1.65
  • Wiki Link: Source Link
  • Element Image: Image Link

Zinc, in commerce also spelter, is a chemical element with symbol Zn and atomic number 30. It is the first element of group 12 of the periodic table. In some respects zinc is chemically similar to magnesium:its ion is of similar size and its only common oxidation state is +2.

Gallium

Discovered State
1875 Solid
Atomic Mass Density
69.7231 5.91 g/L
70 31 Ga
Electrons Protons Neutrons
31 31 39
Electronic Configuration
[Ar] 3d104s24p1
  • Discovered By: Lecoq de Boisbaudran
  • Appearance: silver-white
  • Category: post-transition metal
  • Melting Point: 302.9146 K
  • Boiling Point: 2673 K
  • Ox. State: 1, 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.81
  • Wiki Link: Source Link
  • Element Image: Image Link

Gallium is a chemical element with symbol Ga and atomic number 31. Elemental gallium does not occur in free form in nature, but as the gallium(III) compounds that are in trace amounts in zinc ores and in bauxite. Gallium is a soft, silvery metal, and elemental gallium is a brittle solid at low temperatures, and melts at 29.76 °C (85.57 °F) (slightly above room temperature).

Germanium

Discovered State
1886 Solid
Atomic Mass Density
72.6308 5.323 g/L
73 32 Ge
Electrons Protons Neutrons
32 32 41
Electronic Configuration
[Ar] 3d104s24p2
  • Discovered By: Lecoq de Boisbaudran
  • Appearance: grayish-white
  • Category: metalloid
  • Melting Point: 1211.4 K
  • Boiling Point: 3106 K
  • Ox. State: -4, 1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 2.01
  • Wiki Link: Source Link
  • Element Image: Image Link

Germanium is a chemical element with symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. Purified germanium is a semiconductor, with an appearance most similar to elemental silicon.

Arsenic

Discovered State
Ancient Solid
Atomic Mass Density
74.9215956 5.727 g/L
75 33 As
Electrons Protons Neutrons
33 33 42
Electronic Configuration
[Ar] 3d104s24p3
  • Discovered By: Bronze Age
  • Appearance: metallic grey
  • Category: metalloid
  • Melting Point: 1090 K
  • Boiling Point: 887 K
  • Ox. State: -3, 2, 3, 5
  • Bonding Type: metallic
  • Electronegativity: 2.18
  • Wiki Link: Source Link
  • Element Image: Image Link

Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. Arsenic is a metalloid.

Selenium

Discovered State
1817 Solid
Atomic Mass Density
78.9718 4.81 g/L
79 34 Se
Electrons Protons Neutrons
34 34 45
Electronic Configuration
[Ar] 3d104s24p4
  • Discovered By: Jöns Jakob Berzelius
  • Appearance: black, red
  • Category: polyatomic nonmetal
  • Melting Point: 494 K
  • Boiling Point: 958 K
  • Ox. State: -2, 2, 4, 6
  • Bonding Type: metallic
  • Electronegativity: 2.55
  • Wiki Link: Source Link
  • Element Image: Image Link

Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between those of its periodic table column-adjacent chalcogen elements sulfur and tellurium. It rarely occurs in its elemental state in nature, or as pure ore compounds.

Bromine

Discovered State
1826 Liquid
Atomic Mass Density
79.904 23.1028 g/L
80 35 Br 2
Electrons Protons Neutrons
35 35 45
Electronic Configuration
[Ar] 3d104s24p5
  • Discovered By: Antoine Jérôme Balard
  • Appearance:
  • Category: diatomic nonmetal
  • Melting Point: 265.8 K
  • Boiling Point: 332 K
  • Ox. State: -1, 1, 3, 4, 5, 7
  • Bonding Type: covalent network
  • Electronegativity: 2.96
  • Wiki Link: Source Link
  • Element Image: Image Link

Bromine (from Ancient Greek:βρῶμος, brómos, meaning "stench") is a chemical element with symbol Br, and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826.

Krypton

Discovered State
1898 Gas
Atomic Mass Density
83.7982 3.749 g/L
84 36 Kr
Electrons Protons Neutrons
36 36 48
Electronic Configuration
[Ar] 3d104s24p6
  • Discovered By: William Ramsay
  • Appearance: colorless gas
  • Category: noble gas
  • Melting Point: 115.78 K
  • Boiling Point: 119.93 K
  • Ox. State: 2
  • Bonding Type: atomic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Krypton (from Greek:κρυπτός kryptos "the hidden one") is a chemical element with symbol Kr and atomic number 36. It is a member of group 18 (noble gases) elements. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionally distilling liquefied air, and is often used with other rare gases in fluorescent lamps.

Rubidium

Discovered State
1861 Solid
Atomic Mass Density
85.46783 1.532 g/L
85 37 Rb
Electrons Protons Neutrons
37 37 48
Electronic Configuration
[Kr] 5s1
  • Discovered By: Robert Bunsen
  • Appearance: grey white
  • Category: alkali metal
  • Melting Point: 312.45 K
  • Boiling Point: 961 K
  • Ox. State: 1
  • Bonding Type: metallic
  • Electronegativity: 0.82
  • Wiki Link: Source Link
  • Element Image: Image Link

Rubidium is a chemical element with symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group, with an atomic mass of 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, such as very rapid oxidation in air.

Strontium

Discovered State
1790 Solid
Atomic Mass Density
87.621 2.64 g/L
88 38 Sr
Electrons Protons Neutrons
38 38 50
Electronic Configuration
[Kr] 5s2
  • Discovered By: William Cruickshank (chemist)
  • Appearance:
  • Category: alkaline earth metal
  • Melting Point: 1050 K
  • Boiling Point: 1650 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity: 0.95
  • Wiki Link: Source Link
  • Element Image: Image Link

Strontium is a chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when it is exposed to air.

Yttrium

Discovered State
1794 Solid
Atomic Mass Density
88.905842 4.472 g/L
89 39 Y
Electrons Protons Neutrons
39 39 50
Electronic Configuration
[Kr] 4d15s2
  • Discovered By: Johan Gadolin
  • Appearance: silvery white
  • Category: transition metal
  • Melting Point: 1799 K
  • Boiling Point: 3203 K
  • Ox. State: 1, 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.22
  • Wiki Link: Source Link
  • Element Image: Image Link

Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and it has often been classified as a "rare earth element". Yttrium is almost always found combined with the lanthanides in rare earth minerals and is never found in nature as a free element.

Zirconium

Discovered State
1789 Solid
Atomic Mass Density
91.2242 6.52 g/L
91 40 Zr
Electrons Protons Neutrons
40 40 51
Electronic Configuration
[Kr] 4d25s2
  • Discovered By: Martin Heinrich Klaproth
  • Appearance: silvery white
  • Category: transition metal
  • Melting Point: 2128 K
  • Boiling Point: 4650 K
  • Ox. State: 1, 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.33
  • Wiki Link: Source Link
  • Element Image: Image Link

Zirconium is a chemical element with symbol Zr and atomic number 40. The name of zirconium is taken from the name of the mineral zircon, the most important source of zirconium. The word zircon comes from the Persian word zargun زرگون, meaning "gold-colored".

Niobium

Discovered State
1801 Solid
Atomic Mass Density
92.906372 8.57 g/L
93 41 Nb
Electrons Protons Neutrons
41 41 52
Electronic Configuration
[Kr] 4d45s1
  • Discovered By: Charles Hatchett
  • Appearance: gray metallic, bluish when oxidized
  • Category: transition metal
  • Melting Point: 2750 K
  • Boiling Point: 5017 K
  • Ox. State: -1, 2, 3, 4, 5
  • Bonding Type: metallic
  • Electronegativity: 1.6
  • Wiki Link: Source Link
  • Element Image: Image Link

Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology:Niobe, daughter of Tantalus since it is so similar to tantalum.

Molybdenum

Discovered State
1778 Solid
Atomic Mass Density
95.951 10.28 g/L
96 42 Mo
Electrons Protons Neutrons
42 42 54
Electronic Configuration
[Kr] 4d55s1
  • Discovered By: Carl Wilhelm Scheele
  • Appearance: gray metallic,
  • Category: transition metal
  • Melting Point: 2896 K
  • Boiling Point: 4912 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 2.16
  • Wiki Link: Source Link
  • Element Image: Image Link

Molybdenum is a chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, from Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele.

Technetium

Discovered State
1937 Solid
Atomic Mass Density
98 11 g/L
98 43 Tc
Electrons Protons Neutrons
43 43 55
Electronic Configuration
[Kr] 4d55s2
  • Discovered By: Emilio Segrè
  • Appearance: shiny gray metal
  • Category: transition metal
  • Melting Point: 2430 K
  • Boiling Point: 4538 K
  • Ox. State: -3, -1, 1, 2, 3, 4, 5, 6, 7
  • Bonding Type: metallic
  • Electronegativity: 1.9
  • Wiki Link: Source Link
  • Element Image: Image Link

Technetium (/tɛkˈniːʃiəm/) is a chemical element with symbol Tc and atomic number 43. It is the element with the lowest atomic number in the periodic table that has no stable isotopes:every form of it is radioactive. Nearly all technetium is produced synthetically, and only minute amounts are found in nature.

Ruthenium

Discovered State
1827 Solid
Atomic Mass Density
101.072 12.37 g/L
101 44 Ru
Electrons Protons Neutrons
44 44 57
Electronic Configuration
[Kr] 4d75s1
  • Discovered By: Karl Ernst Claus
  • Appearance: silvery white metallic
  • Category: transition metal
  • Melting Point: 2607 K
  • Boiling Point: 4423 K
  • Ox. State: -2, 1, 2, 3, 4, 5, 6, 7, 8
  • Bonding Type: metallic
  • Electronegativity: 2.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals.

Rhodium

Discovered State
1803 Solid
Atomic Mass Density
101.072 12.41 g/L
103 45 Rh
Electrons Protons Neutrons
45 45 58
Electronic Configuration
[Kr] 4d85s1
  • Discovered By: William Hyde Wollaston
  • Appearance: silvery white metallic
  • Category: transition metal
  • Melting Point: 2237 K
  • Boiling Point: 3968 K
  • Ox. State: -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 2.28
  • Wiki Link: Source Link
  • Element Image: Image Link

Rhodium is a chemical element with symbol Rh and atomic number 45. It is a rare, silvery-white, hard, and chemically inert transition metal. It is a member of the platinum group.

Palladium

Discovered State
1803 Solid
Atomic Mass Density
106.421 12.023 g/L
106 46 Pd
Electrons Protons Neutrons
46 46 60
Electronic Configuration
[Kr] 4d10
  • Discovered By: William Hyde Wollaston
  • Appearance: silvery white
  • Category: transition metal
  • Melting Point: 1828.05 K
  • Boiling Point: 3236 K
  • Ox. State: 2, 4
  • Bonding Type: metallic
  • Electronegativity: 2.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Palladium is a chemical element with symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas.

Silver

Discovered State
Ancient Solid
Atomic Mass Density
107.86822 10.49 g/L
108 47 Ag
Electrons Protons Neutrons
47 47 61
Electronic Configuration
[Kr] 4d105s1
  • Discovered By: unknown, before 5000 BC
  • Appearance: lustrous white metal
  • Category: transition metal
  • Melting Point: 1234.93 K
  • Boiling Point: 2435 K
  • Ox. State: 1, 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.93
  • Wiki Link: Source Link
  • Element Image: Image Link

Silver is a chemical element with symbol Ag (Greek:άργυρος árguros, Latin:argentum, both from the Indo-European root *h₂erǵ- for "grey" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it possesses the highest electrical conductivity, thermal conductivity and reflectivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite.

Cadmium

Discovered State
1817 Solid
Atomic Mass Density
112.4144 8.65 g/L
112 48 Cd
Electrons Protons Neutrons
48 48 64
Electronic Configuration
[Kr] 4d105s2
  • Discovered By: Karl Samuel Leberecht Hermann
  • Appearance: silvery bluish-gray metallic
  • Category: transition metal
  • Melting Point: 594.22 K
  • Boiling Point: 1040 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity: 1.69
  • Wiki Link: Source Link
  • Element Image: Image Link

Cadmium is a chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals.

Indium

Discovered State
1863 Solid
Atomic Mass Density
114.8181 7.31 g/L
115 49 In
Electrons Protons Neutrons
49 49 66
Electronic Configuration
[Kr] 4d105s25p1
  • Discovered By: Ferdinand Reich
  • Appearance: silvery lustrous gray
  • Category: post-transition metal
  • Melting Point: 429.7485 K
  • Boiling Point: 2345 K
  • Ox. State: 1, 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.78
  • Wiki Link: Source Link
  • Element Image: Image Link

Indium is a chemical element with symbol In and atomic number 49. It is a post-transition metallic element that is rare in Earth's crust. The metal is very soft, malleable and easily fusible, with a melting point higher than sodium, but lower than lithium or tin.

Tin

Discovered State
Ancient Solid
Atomic Mass Density
118.7107 7.365 g/L
119 50 Sn
Electrons Protons Neutrons
50 50 69
Electronic Configuration
[Kr] 4d105s25p2
  • Discovered By: unknown, before 3500 BC
  • Appearance: silvery-white (beta, β) or gray (alpha, α)
  • Category: post-transition metal
  • Melting Point: 505.08 K
  • Boiling Point: 2875 K
  • Ox. State: -4, 2, 4
  • Bonding Type: metallic
  • Electronegativity: 1.96
  • Wiki Link: Source Link
  • Element Image: Image Link

Tin is a chemical element with the symbol Sn (for Latin:stannum) and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows a chemical similarity to both neighboring group-14 elements, germanium and lead, and has two possible oxidation states, +2 and the slightly more stable +4.

Antimony

Discovered State
Ancient Solid
Atomic Mass Density
121.7601 6.697 g/L
122 51 Sb
Electrons Protons Neutrons
51 51 71
Electronic Configuration
[Kr] 4d105s25p3
  • Discovered By: unknown, before 3000 BC
  • Appearance: silvery lustrous gray
  • Category: metalloid
  • Melting Point: 903.78 K
  • Boiling Point: 1908 K
  • Ox. State: -3, 3, 5
  • Bonding Type: metallic
  • Electronegativity: 2.05
  • Wiki Link: Source Link
  • Element Image: Image Link

Antimony is a chemical element with symbol Sb (from Latin:stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times and were used for cosmetics; metallic antimony was also known, but it was erroneously identified as lead upon its discovery.

Tellurium

Discovered State
1782 Solid
Atomic Mass Density
127.603 6.24 g/L
128 52 Te
Electrons Protons Neutrons
52 52 76
Electronic Configuration
[Kr] 4d105s25p4
  • Discovered By: Franz-Joseph Müller von Reichenstein
  • Appearance:
  • Category: metalloid
  • Melting Point: 722.66 K
  • Boiling Point: 1261 K
  • Ox. State: -2, 2, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 2.1
  • Wiki Link: Source Link
  • Element Image: Image Link

Tellurium is a chemical element with symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur.

Iodine

Discovered State
1811 Solid
Atomic Mass Density
126.904473 4.933 g/L
127 53 I 2
Electrons Protons Neutrons
53 53 74
Electronic Configuration
[Kr] 4d105s25p5
  • Discovered By: Bernard Courtois
  • Appearance: lustrous metallic gray, violet as a gas
  • Category: halogen
  • Melting Point: 386.85 K
  • Boiling Point: 457.4 K
  • Ox. State: -1, 1, 3, 5, 7
  • Bonding Type: metallic
  • Electronegativity: 2.66
  • Wiki Link: Source Link
  • Element Image: Image Link

Iodine is a chemical element with symbol I and atomic number 53. The name is from Greek ἰοειδής ioeidēs, meaning violet or purple, due to the color of iodine vapor. Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers.

Xenon

Discovered State
1898 Gas
Atomic Mass Density
131.2936 5.894 g/L
131 54 Xe
Electrons Protons Neutrons
54 54 77
Electronic Configuration
[Kr] 4d105s25p6
  • Discovered By: William Ramsay
  • Appearance: colorless gas
  • Category: noble gas
  • Melting Point: 161.4 K
  • Boiling Point: 165.051 K
  • Ox. State: 2, 4, 6, 8
  • Bonding Type: metallic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Xenon is a chemical element with symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas, that occurs in the Earth's atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.

Caesium

Discovered State
1860 Solid
Atomic Mass Density
132.905451966 1.93 g/L
133 55 Cs
Electrons Protons Neutrons
55 55 78
Electronic Configuration
[Xe] 6s1
  • Discovered By: Robert Bunsen
  • Appearance: silvery gold
  • Category: alkali metal
  • Melting Point: 301.7 K
  • Boiling Point: 944 K
  • Ox. State: 1
  • Bonding Type: metallic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Caesium or cesium is a chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C (82 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium is an alkali metal and has physical and chemical properties similar to those of rubidium and potassium.

Barium

Discovered State
1808 Solid
Atomic Mass Density
137.3277 3.51 g/L
137 56 Ba
Electrons Protons Neutrons
56 56 81
Electronic Configuration
[Xe] 6s2
  • Discovered By: Carl Wilhelm Scheele
  • Appearance: silvery gold
  • Category: alkaline earth metal
  • Melting Point: 1000 K
  • Boiling Point: 2118 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity: 0.89
  • Wiki Link: Source Link
  • Element Image: Image Link

Barium is a chemical element with symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Because of its high chemical reactivity barium is never found in nature as a free element.

Lanthanum

Discovered State
1839 Solid
Atomic Mass Density
138.905477 6.162 g/L
139 57 La
Electrons Protons Neutrons
57 57 82
Electronic Configuration
[Xe] 5d16s2
  • Discovered By: Carl Gustaf Mosander
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1193 K
  • Boiling Point: 3737 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.1
  • Wiki Link: Source Link
  • Element Image: Image Link

Lanthanum is a soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It gave its name to the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table:it is also sometimes considered the first element of the 6th-period transition metals.

Cerium

Discovered State
1803 Solid
Atomic Mass Density
140.1161 6.77 g/L
140 58 Ce
Electrons Protons Neutrons
58 58 82
Electronic Configuration
[Xe] 4f15d16s2
  • Discovered By: Martin Heinrich Klaproth
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1068 K
  • Boiling Point: 3716 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.12
  • Wiki Link: Source Link
  • Element Image: Image Link

Cerium is a chemical element with symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet Ceres (itself named after the Roman goddess of agriculture).

Praseodymium

Discovered State
1885 Solid
Atomic Mass Density
140.907662 6.77 g/L
141 59 Pr
Electrons Protons Neutrons
59 59 82
Electronic Configuration
[Xe] 4f36s2
  • Discovered By: Carl Auer von Welsbach
  • Appearance: grayish white
  • Category: lanthanide
  • Melting Point: 1208 K
  • Boiling Point: 3403 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.13
  • Wiki Link: Source Link
  • Element Image: Image Link

Praseodymium is a chemical element with symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is valued for its magnetic, electrical, chemical, and optical properties.

Neodymium

Discovered State
1885 Solid
Atomic Mass Density
144.2423 7.01 g/L
144 60 Nd
Electrons Protons Neutrons
60 60 84
Electronic Configuration
[Xe] 4f46s2
  • Discovered By: Carl Auer von Welsbach
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1297 K
  • Boiling Point: 3347 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.14
  • Wiki Link: Source Link
  • Element Image: Image Link

Neodymium is a chemical element with symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach.

Promethium

Discovered State
1947 Solid
Atomic Mass Density
145 7.26 g/L
145 61 Pm
Electrons Protons Neutrons
61 61 84
Electronic Configuration
[Xe] 4f56s2
  • Discovered By: Chien Shiung Wu
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1315 K
  • Boiling Point: 3273 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.13
  • Wiki Link: Source Link
  • Element Image: Image Link

Promethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements.

Samarium

Discovered State
1853 Solid
Atomic Mass Density
150.362 7.52 g/L
150 62 Sm
Electrons Protons Neutrons
62 62 88
Electronic Configuration
[Xe] 4f66s2
  • Discovered By: Lecoq de Boisbaudran
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1345 K
  • Boiling Point: 2173 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.17
  • Wiki Link: Source Link
  • Element Image: Image Link

Samarium is a chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that readily oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3.

Europium

Discovered State
1901 Solid
Atomic Mass Density
151.9641 5.264 g/L
152 63 Eu
Electrons Protons Neutrons
63 63 89
Electronic Configuration
[Xe] 4f76s2
  • Discovered By: Eugène-Anatole Demarçay
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1099 K
  • Boiling Point: 1802 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Europium is a chemical element with symbol Eu and atomic number 63. It was isolated in 1901 and is named after the continent of Europe. It is a moderately hard, silvery metal which readily oxidizes in air and water.

Gadolinium

Discovered State
1880 Solid
Atomic Mass Density
157.253 7.9 g/L
157 64 Gd
Electrons Protons Neutrons
64 64 93
Electronic Configuration
[Xe] 4f75d16s2
  • Discovered By: Jean Charles Galissard de Marignac
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1585 K
  • Boiling Point: 3273 K
  • Ox. State: 1, 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Gadolinium is a chemical element with symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined (salt) form.

Terbium

Discovered State
1843 Solid
Atomic Mass Density
158.925352 8.23 g/L
159 65 Tb
Electrons Protons Neutrons
65 65 94
Electronic Configuration
[Xe] 4f96s2
  • Discovered By: Carl Gustaf Mosander
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1629 K
  • Boiling Point: 3396 K
  • Ox. State: 1, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Terbium is a chemical element with symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.

Dysprosium

Discovered State
1886 Solid
Atomic Mass Density
162.5001 8.54 g/L
163 66 Dy
Electrons Protons Neutrons
66 66 97
Electronic Configuration
[Xe] 4f96s2
  • Discovered By: Lecoq de Boisbaudran
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1680 K
  • Boiling Point: 2840 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.22
  • Wiki Link: Source Link
  • Element Image: Image Link

Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime.

Holmium

Discovered State
1878 Solid
Atomic Mass Density
164.930332 8.79 g/L
165 67 Ho
Electrons Protons Neutrons
67 67 98
Electronic Configuration
[Xe] 4f116s2
  • Discovered By: Marc Delafontaine
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1734 K
  • Boiling Point: 2873 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.23
  • Wiki Link: Source Link
  • Element Image: Image Link

Holmium is a chemical element with symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare earth element. Holmium was discovered by Swedish chemist Per Theodor Cleve.

Erbium

Discovered State
1842 Solid
Atomic Mass Density
167.2593 9.066 g/L
167 68 Er
Electrons Protons Neutrons
68 68 99
Electronic Configuration
[Xe] 4f126s2
  • Discovered By: Carl Gustaf Mosander
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1802 K
  • Boiling Point: 3141 K
  • Ox. State: 3
  • Bonding Type: metallic
  • Electronegativity: 1.24
  • Wiki Link: Source Link
  • Element Image: Image Link

Erbium is a chemical element in the lanthanide series, with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth. As such, it is a rare earth element which is associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden, where yttrium, ytterbium, and terbium were discovered.

Thulium

Discovered State
1879 Solid
Atomic Mass Density
168.934222 9.32 g/L
169 69 Tm
Electrons Protons Neutrons
69 69 100
Electronic Configuration
[Xe] 4f136s2
  • Discovered By: Per Teodor Cleve
  • Appearance: silvery gray
  • Category: lanthanide
  • Melting Point: 1818 K
  • Boiling Point: 2223 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.25
  • Wiki Link: Source Link
  • Element Image: Image Link

Thulium is a chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate (third-last) element in the lanthanide series. Like the other lanthanides, the most common oxidation state is +3, seen in its oxide, halides and other compounds.

Ytterbium

Discovered State
1878 Solid
Atomic Mass Density
173.0451 6.9 g/L
173 70 Yb
Electrons Protons Neutrons
70 70 103
Electronic Configuration
[Xe] 4f146s2
  • Discovered By: Jean Charles Galissard de Marignac
  • Appearance: silvery gray
  • Category: lanthanide
  • Melting Point: 1097 K
  • Boiling Point: 1469 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.1
  • Wiki Link: Source Link
  • Element Image: Image Link

Ytterbium is a chemical element with symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. However, like the other lanthanides, its most common oxidation state is +3, seen in its oxide, halides and other compounds.

Lutetium

Discovered State
1907 Solid
Atomic Mass Density
174.96681 9.841 g/L
175 71 Lu
Electrons Protons Neutrons
71 71 104
Electronic Configuration
[Xe] 4f145d16s2
  • Discovered By: Georges Urbain
  • Appearance: silvery white
  • Category: lanthanide
  • Melting Point: 1925 K
  • Boiling Point: 3675 K
  • Ox. State: 3
  • Bonding Type: metallic
  • Electronegativity: 1.27
  • Wiki Link: Source Link
  • Element Image: Image Link

Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry, but not in moist air. It is considered the first element of the 6th-period transition metals and the last element in the lanthanide series, and is traditionally counted among the rare earths.

Hafnium

Discovered State
1923 Solid
Atomic Mass Density
178.492 13.31 g/L
178 72 Hf
Electrons Protons Neutrons
72 72 106
Electronic Configuration
[Xe] 4f145d26s2
  • Discovered By: Dirk Coster
  • Appearance: steel gray
  • Category: transition metal
  • Melting Point: 2506 K
  • Boiling Point: 4876 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Hafnium is a chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, making it the penultimate stable element to be discovered (rhenium was identified two years later).

Tantalum

Discovered State
1802 Solid
Atomic Mass Density
180.947882 16.69 g/L
181 73 Ta
Electrons Protons Neutrons
73 73 108
Electronic Configuration
[Xe] 4f145d36s2
  • Discovered By: Anders Gustaf Ekeberg
  • Appearance: gray blue
  • Category: transition metal
  • Melting Point: 3290 K
  • Boiling Point: 5731 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.5
  • Wiki Link: Source Link
  • Element Image: Image Link

Tantalum is a chemical element with symbol Ta and atomic number 73. Previously known as tantalium, its name comes from Tantalus, an antihero from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant.

Tungsten

Discovered State
1783 Solid
Atomic Mass Density
183.841 19.25 g/L
184 74 W
Electrons Protons Neutrons
74 74 110
Electronic Configuration
[Xe] 4f145d46s2
  • Discovered By: Carl Wilhelm Scheele
  • Appearance: grayish white, lustrous
  • Category: transition metal
  • Melting Point: 3695 K
  • Boiling Point: 6203 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 2.36
  • Wiki Link: Source Link
  • Element Image: Image Link

Tungsten, also known as wolfram, is a chemical element with symbol W and atomic number 74. The word tungsten comes from the Swedish language tung sten, which directly translates to heavy stone. Its name in Swedish is volfram, however, in order to distinguish it from scheelite, which in Swedish is alternatively named tungsten.

Rhenium

Discovered State
1925 Solid
Atomic Mass Density
186.2071 21.02 g/L
186 75 Re
Electrons Protons Neutrons
75 75 111
Electronic Configuration
[Xe] 4f145d56s2
  • Discovered By: Masataka Ogawa
  • Appearance: silvery-grayish
  • Category: transition metal
  • Melting Point: 3459 K
  • Boiling Point: 5869 K
  • Ox. State: -3, -1, 1, 2, 3, 4, 5, 6, 7
  • Bonding Type: metallic
  • Electronegativity: 1.9
  • Wiki Link: Source Link
  • Element Image: Image Link

Rhenium is a chemical element with symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust.

Osmium

Discovered State
1803 Solid
Atomic Mass Density
190.233 22.59 g/L
187 76 Os
Electrons Protons Neutrons
76 76 111
Electronic Configuration
[Xe] 4f145d66s2
  • Discovered By: Smithson Tennant
  • Appearance: silvery, blue cast
  • Category: transition metal
  • Melting Point: 3306 K
  • Boiling Point: 5285 K
  • Ox. State: -2, -1, 1, 2, 3, 4, 5, 6, 7, 8
  • Bonding Type: metallic
  • Electronegativity: 2.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Osmium (from Greek osme (ὀσμή) meaning "smell") is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with a density of 22.59 g/cm3.

Iridium

Discovered State
1803 Solid
Atomic Mass Density
192.2173 22.56 g/L
192 77 Ir
Electrons Protons Neutrons
77 77 115
Electronic Configuration
[Xe] 4f145d76s2
  • Discovered By: Smithson Tennant
  • Appearance: silvery white
  • Category: transition metal
  • Melting Point: 2719 K
  • Boiling Point: 4403 K
  • Ox. State: -3, -1, 1, 2, 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 2.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Iridium is a chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is generally credited with being the second densest element (after osmium) based on measured density, although calculations involving the space lattices of the elements show that iridium is denser. It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C. Although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable.

Platinum

Discovered State
Ancient Solid
Atomic Mass Density
195.0849 21.45 g/L
195 78 Pt
Electrons Protons Neutrons
78 78 117
Electronic Configuration
[Xe] 4f145d96s1
  • Discovered By: Antonio de Ulloa
  • Appearance: silvery white
  • Category: transition metal
  • Melting Point: 2041.4 K
  • Boiling Point: 4098 K
  • Ox. State: 2, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 2.28
  • Wiki Link: Source Link
  • Element Image: Image Link

Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, gray-white transition metal. Its name is derived from the Spanish term platina, which is literally translated into "little silver".

Gold

Discovered State
Ancient Solid
Atomic Mass Density
196.9665695 19.3 g/L
197 79 Au
Electrons Protons Neutrons
79 79 118
Electronic Configuration
[Xe] 4f145d106s1
  • Discovered By: Middle East
  • Appearance: metallic yellow
  • Category: transition metal
  • Melting Point: 1337.33 K
  • Boiling Point: 3243 K
  • Ox. State: -1, 1, 2, 3, 5
  • Bonding Type: metallic
  • Electronegativity: 2.54
  • Wiki Link: Source Link
  • Element Image: Image Link

Gold is a chemical element with symbol Au (from Latin:aurum) and atomic number 79. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable and ductile metal. Chemically, gold is a transition metal and a group 11 element.

Mercury

Discovered State
Ancient Liquid
Atomic Mass Density
200.5923 13.534 g/L
201 80 Hg
Electrons Protons Neutrons
80 80 121
Electronic Configuration
[Xe] 4f145d106s2
  • Discovered By: unknown, before 2000 BCE
  • Appearance: silvery
  • Category: transition metal
  • Melting Point: 234.321 K
  • Boiling Point: 629.88 K
  • Ox. State: 1, 2, 4
  • Bonding Type: metallic
  • Electronegativity: 2
  • Wiki Link: Source Link
  • Element Image: Image Link

Mercury is a chemical element with symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum (/haɪˈdrɑːrdʒərəm/). A heavy, silvery d-block element, mercury is the only metallic element that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.

Thallium

Discovered State
1861 Solid
Atomic Mass Density
204.38 11.85 g/L
204 81 Tl
Electrons Protons Neutrons
81 81 123
Electronic Configuration
[Xe] 4f145d106s26p1
  • Discovered By: William Crookes
  • Appearance: silvery white
  • Category: post-transition metal
  • Melting Point: 577 K
  • Boiling Point: 1746 K
  • Ox. State: 1, 3
  • Bonding Type: metallic
  • Electronegativity: 2.04
  • Wiki Link: Source Link
  • Element Image: Image Link

Thallium is a chemical element with symbol Tl and atomic number 81. This soft gray post-transition metal is not found free in nature. When isolated, it resembles tin, but discolors when exposed to air.

Lead

Discovered State
Ancient Solid
Atomic Mass Density
207.21 11.34 g/L
208 82 Pb
Electrons Protons Neutrons
82 82 126
Electronic Configuration
[Xe] 4f145d106s26p2
  • Discovered By: Middle East
  • Appearance: metallic gray
  • Category: post-transition metal
  • Melting Point: 600.61 K
  • Boiling Point: 2022 K
  • Ox. State: -4, 2, 4
  • Bonding Type: metallic
  • Electronegativity: 2.33
  • Wiki Link: Source Link
  • Element Image: Image Link

Lead (/lɛd/) is a chemical element in the carbon group with symbol Pb (from Latin:plumbum) and atomic number 82. Lead is a soft, malleable and heavy post-transition metal. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air.

Bismuth

Discovered State
Ancient Solid
Atomic Mass Density
208.980401 9.78 g/L
206 83 Bi
Electrons Protons Neutrons
83 83 123
Electronic Configuration
[Xe] 4f145d106s26p3
  • Discovered By: Claude François Geoffroy
  • Appearance: lustrous silver
  • Category: post-transition metal
  • Melting Point: 544.7 K
  • Boiling Point: 1837 K
  • Ox. State: -3, 3, 5
  • Bonding Type: metallic
  • Electronegativity: 2.02
  • Wiki Link: Source Link
  • Element Image: Image Link

Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a pentavalent post-transition metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally, although its sulfide and oxide form important commercial ores.

Polonium

Discovered State
1898 Solid
Atomic Mass Density
209 9.196 g/L
209 84 Po
Electrons Protons Neutrons
84 84 125
Electronic Configuration
[Xe] 4f145d106s26p4
  • Discovered By: Pierre Curie
  • Appearance: silvery
  • Category: post-transition metal
  • Melting Point: 527 K
  • Boiling Point: 1235 K
  • Ox. State: -2, 2, 4, 6
  • Bonding Type: metallic
  • Electronegativity: 2
  • Wiki Link: Source Link
  • Element Image: Image Link

Polonium is a chemical element with symbol Po and atomic number 84, discovered in 1898 by Marie Curie and Pierre Curie. A rare and highly radioactive element with no stable isotopes, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Applications of polonium are few.

Astatine

Discovered State
1940 Solid
Atomic Mass Density
210 26.35 g/L
210 85 At
Electrons Protons Neutrons
85 85 125
Electronic Configuration
[Xe] 4f145d106s26p5
  • Discovered By: Dale R. Corson
  • Appearance: silvery
  • Category: metalloid
  • Melting Point: 575 K
  • Boiling Point: 610 K
  • Ox. State: -1, 1, 3, 5
  • Bonding Type: metallic
  • Electronegativity: 2.2
  • Wiki Link: Source Link
  • Element Image: Image Link

Astatine is a very rare radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth as the decay product of various heavier elements. All its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours.

Radon

Discovered State
1900 Gas
Atomic Mass Density
222 9.73 g/L
222 86 Rn
Electrons Protons Neutrons
86 86 136
Electronic Configuration
[Xe] 4f145d106s26p6
  • Discovered By: Friedrich Ernst Dorn
  • Appearance: colorless gas
  • Category: noble gas
  • Melting Point: 202 K
  • Boiling Point: 211.5 K
  • Ox. State: 2
  • Bonding Type: metallic
  • Electronegativity:
  • Wiki Link: Source Link
  • Element Image: Image Link

Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Its most stable isotope, 222Rn, has a half-life of 3.8 days.

Francium

Discovered State
1939 Solid
Atomic Mass Density
223 1.87 g/L
223 87 Fr
Electrons Protons Neutrons
87 87 136
Electronic Configuration
[Rn] 7s1
  • Discovered By: Marguerite Perey
  • Appearance:
  • Category: alkali metal
  • Melting Point: 300 K
  • Boiling Point: 950 K
  • Ox. State: 1
  • Bonding Type: metallic
  • Electronegativity: 0.7
  • Wiki Link: Source Link
  • Element Image: Image Link

Francium is a chemical element with symbol Fr and atomic number 87. It used to be known as eka-caesium and actinium K. It is the second-least electronegative element, behind only caesium. Francium is a highly radioactive metal that decays into astatine, radium, and radon.

Radium

Discovered State
1898 Solid
Atomic Mass Density
226 5.5 g/L
226 88 Ra
Electrons Protons Neutrons
88 88 138
Electronic Configuration
[Rn] 7s2
  • Discovered By: Pierre Curie
  • Appearance:
  • Category: alkaline earth metal
  • Melting Point: 1233 K
  • Boiling Point: 2010 K
  • Ox. State: 3
  • Bonding Type: metallic
  • Electronegativity: 0.9
  • Wiki Link: Source Link
  • Element Image: Image Link

Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is almost colorless, but it readily combines with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (Ra3N2).

Actinium

Discovered State
1898 Solid
Atomic Mass Density
226 10 g/L
227 89 Ac
Electrons Protons Neutrons
89 89 138
Electronic Configuration
[Rn] 6d17s2
  • Discovered By: Friedrich Oskar Giesel
  • Appearance:
  • Category: actinide
  • Melting Point: 1500 K
  • Boiling Point: 3500 K
  • Ox. State: 3
  • Bonding Type: metallic
  • Electronegativity: 1.1
  • Wiki Link: Source Link
  • Element Image: Image Link

Actinium is a radioactive chemical element with symbol Ac (not to be confused with the abbreviation for an acetyl group) and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated. Polonium, radium and radon were observed before actinium, but they were not isolated until 1902.

Thorium

Discovered State
1828 Solid
Atomic Mass Density
232.03774 11.724 g/L
232 90 Th
Electrons Protons Neutrons
90 90 142
Electronic Configuration
[Rn] 6d27s2
  • Discovered By: Jöns Jakob Berzelius
  • Appearance: silvery
  • Category: actinide
  • Melting Point: 2023 K
  • Boiling Point: 5061 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium). It was discovered in 1828 by the Norwegian Reverend and amateur mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius, who named it after Thor, the Norse god of thunder.

Protactinium

Discovered State
1913 Solid
Atomic Mass Density
231.035882 15.37 g/L
231 91 Pa
Electrons Protons Neutrons
91 91 140
Electronic Configuration
[Rn] 5f2 6d1 7s2
  • Discovered By: William Crookes
  • Appearance: bright, silvery metallic luster
  • Category: actinide
  • Melting Point: 1841 K
  • Boiling Point: 4300 K
  • Ox. State: 3, 4, 5
  • Bonding Type: metallic
  • Electronegativity: 1.5
  • Wiki Link: Source Link
  • Element Image: Image Link

Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.

Uranium

Discovered State
1789 Solid
Atomic Mass Density
238.028913 19.1 g/L
238 92 U
Electrons Protons Neutrons
92 92 146
Electronic Configuration
[Rn] 5f3 6d1 7s2
  • Discovered By: Martin Heinrich Klaproth
  • Appearance:
  • Category: actinide
  • Melting Point: 1405.3 K
  • Boiling Point: 4404 K
  • Ox. State: 3, 4, 5, 6
  • Bonding Type: metallic
  • Electronegativity: 1.38
  • Wiki Link: Source Link
  • Element Image: Image Link

Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-white metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons.

Neptunium

Discovered State
1940 Solid
Atomic Mass Density
237 20.45 g/L
237 93 Np
Electrons Protons Neutrons
93 93 144
Electronic Configuration
[Rn] 5f3 6d1 7s2
  • Discovered By: Edwin McMillan
  • Appearance:
  • Category: actinide
  • Melting Point: 912 K
  • Boiling Point: 4447 K
  • Ox. State: 3, 4, 5, 6, 7
  • Bonding Type: metallic
  • Electronegativity: 1.36
  • Wiki Link: Source Link
  • Element Image: Image Link

Neptunium is a chemical element with symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.

Plutonium

Discovered State
1940 Solid
Atomic Mass Density
244 19.816 g/L
333 94 Pu
Electrons Protons Neutrons
94 94 239
Electronic Configuration
[Rn] 5f6 7s2
  • Discovered By: Glenn T. Seaborg
  • Appearance: silvery white
  • Category: actinide
  • Melting Point: 912.5 K
  • Boiling Point: 3505 K
  • Ox. State: 3, 4, 5, 6, 7
  • Bonding Type: metallic
  • Electronegativity: 1.28
  • Wiki Link: Source Link
  • Element Image: Image Link

Plutonium is a transuranic radioactive chemical element with symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states.

Americium

Discovered State
1944 Solid
Atomic Mass Density
243 12 g/L
243 95 Am
Electrons Protons Neutrons
95 95 148
Electronic Configuration
[Rn] 5f7 7s2
  • Discovered By: Glenn T. Seaborg
  • Appearance: silvery white
  • Category: actinide
  • Melting Point: 1449 K
  • Boiling Point: 2880 K
  • Ox. State: 3, 4, 5, 6, 7
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.

Curium

Discovered State
1944 Solid
Atomic Mass Density
247 13.51 g/L
247 96 Cm
Electrons Protons Neutrons
96 96 151
Electronic Configuration
[Rn] 5f7 6d1 7s2
  • Discovered By: Glenn T. Seaborg
  • Appearance: silvery metallic
  • Category: actinide
  • Melting Point: 1613 K
  • Boiling Point: 3383 K
  • Ox. State: 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Curium is a transuranic radioactive chemical element with symbol Cm and atomic number 96. This element of the actinide series was named after Marie and Pierre Curie – both were known for their research on radioactivity. Curium was first intentionally produced and identified in July 1944 by the group of Glenn T. Seaborg at the University of California, Berkeley.

Berkelium

Discovered State
1949 Solid
Atomic Mass Density
247 14.78 g/L
247 97 Bk
Electrons Protons Neutrons
97 97 150
Electronic Configuration
[Rn] 5f9 7s2
  • Discovered By: Lawrence Berkeley National Laboratory
  • Appearance: silvery
  • Category: actinide
  • Melting Point: 1259 K
  • Boiling Point: 2900 K
  • Ox. State: 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Berkelium is a transuranic radioactive chemical element with symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the University of California Radiation Laboratory where it was discovered in December 1949.

Californium

Discovered State
1950 Solid
Atomic Mass Density
251 15.1 g/L
251 98 Cf
Electrons Protons Neutrons
98 98 153
Electronic Configuration
[Rn] 5f10 7s2
  • Discovered By: Lawrence Berkeley National Laboratory
  • Appearance: silvery
  • Category: actinide
  • Melting Point: 1173 K
  • Boiling Point: 1743 K
  • Ox. State: 2, 3, 4
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Californium is a radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium).

Einsteinium

Discovered State
1950 Solid
Atomic Mass Density
252 8.84 g/L
252 99 Es
Electrons Protons Neutrons
99 99 153
Electronic Configuration
[Rn] 5f11 7s2
  • Discovered By: Lawrence Berkeley National Laboratory
  • Appearance: silvery
  • Category: actinide
  • Melting Point: 1133 K
  • Boiling Point: 1269 K
  • Ox. State: 2, 3
  • Bonding Type: metallic
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Einsteinium is a synthetic element with symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide. Einsteinium was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein.

Fermium

Discovered State
1952 Solid
Atomic Mass Density
257 g/L
257 100 Fm
Electrons Protons Neutrons
100 100 157
Electronic Configuration
[Rn] 5f12 7s2
  • Discovered By: Lawrence Berkeley National Laboratory
  • Appearance:
  • Category: actinide
  • Melting Point: 1800 K
  • Boiling Point: K
  • Ox. State: 2, 3
  • Bonding Type:
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Fermium is a synthetic element with symbol Fm and atomic number 100. It is a member of the actinide series. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.

Mendelevium

Discovered State
1955 Solid
Atomic Mass Density
258 g/L
258 101 Md
Electrons Protons Neutrons
101 101 157
Electronic Configuration
[Rn] 5f13 7s2
  • Discovered By: Lawrence Berkeley National Laboratory
  • Appearance:
  • Category: actinide
  • Melting Point: 1100 K
  • Boiling Point: K
  • Ox. State: 2, 3
  • Bonding Type:
  • Electronegativity: 1.3
  • Wiki Link: Source Link
  • Element Image: Image Link

Mendelevium is a synthetic element with chemical symbol Md (formerly Mv) and atomic number 101. A metallic radioactive transuranic element in the actinide series, it is the first element that currently cannot be produced in macroscopic quantities through neutron bombardment of lighter elements. It is the antepenultimate actinide and the ninth transuranic element.

コメント

タイトルとURLをコピーしました