Atomic Number 19     Atomic Mass 39.0983     Density 0.86 g/mL

State solid     Color silvery white     Electronegativity 0.82

Melting Point 63.25°C     Boiling Point 760°C

Natural Isotopes  K-39 93.2581%   K-40 0.0117%   K-41 6.7302%

Abbreviated Electron Configuration [Ar] 4s¹

Discovered by Sir Humphrey Davy in 1807.