Atomic Number 57     Atomic Mass 138.9055     Density 6.14 g/mL

State solid     Color silvery white     Electronegativity 1.1

Melting Point 921°C     Boiling Point 3457°C

Natural Isotopes La-138 0.0902%   La-139 99.9098%

Abbreviated Electron Configuration [Xe] 5d¹ 6s²

Discovered by Carl Mosander in 1839.