Atomic symbol: Ba
Atomic number: 56
Atomic mass: 137.33

Appearance: Silvery gray at 25°C

Group: 2\ Period: 6
Series: Alkaline earth metals
Block: s
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 5s²

Extremely reactive and very toxic: even a small amount can be fatal.

Used in paint, glassmaking, X-ray imaging, and superconductors.

Fun Fact! Barium is combined with sulfur, barium sulfate, and ingested by patients having their digestive system imaged, since it increases the contrast in x-ray imaging. This is because barium sulfate (barite) is highly insoluble in water and completely removed from the digestive tract, meaning that unlike most barium compounds, for this function it is non-toxic.