Atomic Element Z = 56 • Alkaline Earth Metal
Barium (Ba) — Atomic Data, Electron Shells & Reactions
Barium (symbol Ba, atomic number 56) has a standard atomic weight of 137.33 u and ground-state configuration [Xe] 6s2.
Atomic Number (Z)
56
IUPAC Symbol
Ba
Standard Atomic Weight
137.33 g/mol
Period / Group / Block
6 / 2 / s-block
Condensed Electron Config
[Xe] 6s2
Full Subshell Config
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s2
Principal Shell Occupancy
[2, 8, 18, 18, 8, 2]
Pauling Electronegativity
0.89
First Ionization Energy
503 kJ/mol
Covalent Radius
215 pm
Melting Point
1000 K (726.85 °C)
Boiling Point
2118 K (1844.85 °C)
Density
3.594 g/cm³
Oxidation States
+2
Ba (Z=56) — Valence shell highlighted in vermilion