From Wikipedia, the free encyclopediaBarium 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. | |||||||
Barium in the periodic table | |||||||
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Symbol | Ba | ||||||
Atomic number | 56 | ||||||
Group | 2 | ||||||
Period | 6 | ||||||
Block | s | ||||||
Element category | Alkaline Earth Metal | ||||||
Physical properties | |||||||
Phase at STP | Solid | ||||||
Density | 3.51 g/cm3 | ||||||
Atomic weight | 137.328 u | ||||||
Melting point | 1000 K 726.85 °C 1340.33 °F | ||||||
Boiling point | 2118 K 1844.85 °C 3352.73 °F | ||||||
Atomic properties | |||||||
Electronegativity (Pauling Scale) | 0.89 | ||||||
Electron affinity | 13.954 kJ/mol | ||||||
Oxidation states | +1, +2 (a strongly basic oxide) | ||||||
Ionization energies |
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Electron configuration | |||||||
Elektronkonfiguration (shorthand) | [Xe] 6s2 | ||||||
Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s2 | ||||||
Electrons per shell | 2, 8, 18, 18, 8, 2 | ||||||
History | |||||||
Discovered | 1772 | ||||||
Discovered by | Carl Wilhelm Scheele |