56 Ba 137.328

Barium

alkaline earth metal

Properties

Atomic number
56
Atomic mass
137.328 u
Category
alkaline earth metal
Group
2
Period
6
Block
s-block
State (room temp)
Solid
Outer-shell electrons
2
Electronegativity
0.89 (Pauling)
Density
3.51 g/cm³
Melting point
726.85 °C
Boiling point
1844.85 °C

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s²

Noble-gas shorthand: [Xe] 6s²

Electrons per shell: 2, 8, 18, 18, 8, 2 — that's 2 in the outermost shell.

See how electron configuration is built →

Ba
Bohr model — outer-shell electrons in blue

About Barium

Barium 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.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.