Periodic Table
56
Ba
137.33
Barium
Alkaline EarthApple-green flame; BaSO₄ radiocontrast ('barium meal').
Electronic Configuration
[Xe] 6s²or1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s²
Electron shells
2e⁻n=1
8e⁻n=2
18e⁻n=3
18e⁻n=4
8e⁻n=5
2e⁻n=6
Properties
Atomic number
56
Atomic mass
137.33 u
Category
Alkaline Earth
Block / Group / Period
s · 2 · 6
Valence electrons
2
Oxidation states
+2
Electronegativity
0.89
Atomic radius
253 pm
Ionization energy
503 kJ/mol
Electron affinity
14 kJ/mol
Melting point
1000 K / 727 °C
Boiling point
2170 K / 1897 °C
Density
3.594 g/cm³
State at 25 °C
solid
Personal Notes
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