Cesium

Alkali metal · 132.9054520 u · group 1, period 6

Cesium · Cs

Atomic number55

SymbolCs

CategoryAlkali metal

Standard stateSolid

Group · Period · Block1 · 6 · s

Electron configuration[Xe]6s1

Atomic mass132.9054520 u

Atomic radius343 pm

Protons / Neutrons / Electrons55 / 78 / 55

Shells (e⁻ per shell)2, 8, 18, 18, 8, 1

Electronegativity (Pauling)0.79

Ionization energy3.894 eV

Electron affinity0.472 eV

Oxidation states+1

Melting point301.6 K · 28.4 °C

Boiling point944 K · 670.9 °C

Density1.93 g/cm³

Year discovered1860

CPK color

#57178F

State at room temp (25 °C)

solid

Position