Cesium (Cs)

A fascinating alkali metal element.

Cesium is element 55 on the periodic table.

Element properties

Atomic number

55

Symbol

Cs

Atomic mass

132.91 u

Category

Alkali Metal

Period

6

Group

1

Block

s

State

Solid

Electron configuration

[Xe] 6s1

Electronegativity (Pauling)

0.79

Density

1.93 g/cm³

Melting point

28.5 °C

Boiling point

671 °C