Rubidium

Alkali metal · 85.468 u · group 1, period 5

Rubidium · Rb

Atomic number37

SymbolRb

CategoryAlkali metal

Standard stateSolid

Group · Period · Block1 · 5 · s

Electron configuration[Kr]5s1

Atomic mass85.468 u

Atomic radius303 pm

Protons / Neutrons / Electrons37 / 48 / 37

Shells (e⁻ per shell)2, 8, 18, 8, 1

Electronegativity (Pauling)0.82

Ionization energy4.177 eV

Electron affinity0.468 eV

Oxidation states+1

Melting point312.5 K · 39.3 °C

Boiling point961 K · 687.9 °C

Density1.53 g/cm³

Year discovered1861

CPK color

#702EB0

State at room temp (25 °C)

solid

Position