Atomic Number 37     Atomic Mass 85.4678      Density 1.538 g/mL

State solid     Color silvery white     Electronegativity 0.82

Melting Point 38.89°C    Boiling Point 686°C

Natural Isotopes  Rb-85 72.165%   Rb-87 27.835%

Abbreviated Electron Configuration [Kr] 5s¹

Discovered by Robert Bunsen and Gustav Kirchhoff in 1861.