Lanthanum

Lanthanide · 138.9055 u · group 3, period 6

Lanthanum · La

Atomic number57

SymbolLa

CategoryLanthanide

Standard stateSolid

Group · Period · Block3 · 6 · f

Electron configuration[Xe]6s2 5d1

Atomic mass138.9055 u

Atomic radius240 pm

Protons / Neutrons / Electrons57 / 82 / 57

Shells (e⁻ per shell)2, 8, 18, 18, 9, 2

Electronegativity (Pauling)1.1

Ionization energy5.577 eV

Electron affinity0.5 eV

Oxidation states+3

Melting point1.19e+3 K · 917.9 °C

Boiling point3.74e+3 K · 3.46e+3 °C

Density6.15 g/cm³

Year discovered1839

CPK color

#70D4FF

State at room temp (25 °C)

solid

Position