Potassium (K)

Potassium is a chemical element with symbol K and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives.

Atomic Number

19

Atomic Mass

39.098 u

Category

alkali metal

Phase

solid

Density

0.89 g/cm³

Electron Shells

2, 8, 8, 1

Atomic Structure

Protons: 19 • Electrons: 19 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

Discovery

1807 • Humphry Davy