Potassium
Chemical element
Potassium is a chemical element; it has symbol K and atomic number 19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in... Wikipedia
Symbol: K
Atomic mass: 39.0983 u
Atomic number: 19
Electron configuration: [Ar] 4s¹
Molar mass: 39.0983 g/mol
Group: group 1: hydrogen and alkali metals
Heat of fusion: 2.33 kJ/mol