Atomic number 56
Barium
Alkaline earth metal
Quick facts
- Atomic mass
- 137.33
- Group
- 2
- Period
- 6
- State (STP)
- solid
- Electronegativity
- 0.89
- Common ox. states
- +2
Properties
Electron configuration
[Xe] 6s²
- Ionization energy
- 502.9 kJ/mol
- Electron affinity
- 13.9 kJ/mol
- Melting point
- 1000.00 K (726.9 °C)
- Boiling point
- 2118.00 K (1844.8 °C)
How it bonds
Barium loses both 6s electrons to give Ba²⁺ in salts (BaSO₄, the "barium meal" used in X-ray imaging — insoluble enough that the toxic Ba²⁺ never gets absorbed). Burns green in fireworks.