Symbol: Rb
Atomic number: 37
Atomic weight: 85.47
Soft silvery metallic element, belongs to group 1 of the periodic table. Rb-97, the naturally occurring isotope, is radioactive. It is highly reactive, with properties similar to other elements in group 1, like
igniting spontaneously in air. Discovered spectroscopically in 1861 by W.
Bunsen and G.R. Kirchoff.