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, which is 2 in the outermost shell.

Related: electron configuration, the Bohr model, valence electrons.

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.

Barium: frequently asked questions

What is Barium?
Barium (Ba) is the chemical element with atomic number 56. It is a metal: specifically an alkaline earth metal.
What is the atomic number of Barium?
Barium's atomic number is 56, which means every Barium atom has 56 protons in its nucleus.
What is the electron configuration of Barium?
The electron configuration of Barium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 (noble-gas shorthand: [Xe] 6s2). Its electrons are arranged in shells of 2, 8, 18, 18, 8, 2, with 2 in the outermost shell.
Is Barium a metal or a nonmetal?
Barium is a metal: specifically an alkaline earth metal.
What group and period is Barium in?
Barium is in group 2 and period 6 of the periodic table.
Is Barium a solid, liquid, or gas?
At room temperature, Barium is a solid.

Position in the periodic table

Open the interactive periodic table →

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