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19K

Potassium

Alkali metal · 39.0983 u · group 1, period 4

Potassium · K

Identity

Atomic number19

SymbolK

CategoryAlkali metal

Standard stateSolid

Group · Period · Block1 · 4 · s

Electron configuration[Ar]4s1

Atomic

Atomic mass39.0983 u

Atomic radius275 pm

Protons / Neutrons / Electrons19 / 20 / 19

Shells (e⁻ per shell)2, 8, 8, 1

Chemical

Electronegativity (Pauling)0.82

Ionization energy4.341 eV

Electron affinity0.501 eV

Oxidation states+1

Physical

Melting point336.5 K · 63.4 °C

Boiling point1.03e+3 K · 758.9 °C

Density0.89 g/cm³

History

Year discovered1807

CPK color

#8F40D4

State at room temp (25 °C)

solid

Position