Potassium

19 argon ← potassium → calcium Na ↑ K ↓ Rb periodic table General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39.0983(1) g/mol Electron configuration [Ar] 4s1 Electrons per shell 2, 8, 8, 1 Physical properties Phase solid Density (near r.t.) 0.89 g·cm−3 Liquid density at m.p. 0.828 g·cm−3 Melting point 336.53 K (63.38 °C, 146.08  ...