Barium

Alkaline earth metal · 137.33 u · group 2, period 6

Barium · Ba

Atomic number56

SymbolBa

CategoryAlkaline earth metal

Standard stateSolid

Group · Period · Block2 · 6 · s

Electron configuration[Xe]6s2

Atomic mass137.33 u

Atomic radius268 pm

Protons / Neutrons / Electrons56 / 81 / 56

Shells (e⁻ per shell)2, 8, 18, 18, 8, 2

Electronegativity (Pauling)0.89

Ionization energy5.212 eV

Electron affinity—

Oxidation states+2

Melting point1.00e+3 K · 726.9 °C

Boiling point2.17e+3 K · 1.90e+3 °C

Density3.62 g/cm³

Year discovered1808

CPK color

#00C900

State at room temp (25 °C)

solid

Position