19 K

Alkali metal

Potassium

Vital for nerves and plants.

See it in the interactive periodic table

Properties of Potassium

Atomic number (Z)
19
Symbol
K
Atomic mass
39.098 g/mol
Category
Alkali metal
Group
1
Period
4
Electron configuration
[Ar] 4s¹
Electronegativity (Pauling)
0.82
Atomic radius
243 pm
First ionization energy
419 kJ/mol
Melting point
336.53 K (63.4 °C)
Boiling point
1032 K (758.9 °C)
Density
0.862 g/cm³
Phase at 25 °C
Solid
Discovered
Discovered in 1807
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