Potassium

Document v1 · published by Koskamo · updated 2026-10-04

Potassium (K) is chemical element 19, an alkali metal in group 1, period 4 (PubChem).

Atomic number: 19
Symbol: K
Group: 1
Period: 4
Atomic mass: 39.0983 u
Electron configuration: [Ar]4s1
Electronegativity (Pauling scale): 0.82
Atomic radius (van der Waals): 275 pm
Ionization energy: 4.341 eV
Electron affinity: 0.501 eV
Oxidation states: +1
Standard state: Solid
Melting point: 336.53 K
Boiling point: 1032 K
Density: 0.89 g/cm³
Chemical group: Alkali metal
Year discovered: 1807

Source and provenance

Original source: pubchem.ncbi.nlm.nih.gov
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: PubChem periodic table data (NIH/NLM, pubchem.ncbi.nlm.nih.gov/ptable); group and period from Jefferson Lab via PubChem

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Version history

Published by Koskamo2026-10-04
Version 1