19
K
potassium
39.098

General properties

Group
group 1 (H and alkali metals)
Period
period 4
Category
alkali metals
Standard atomic weight
39.0983(1)
Melting point
336.7 K (63.6 °C)
Boiling point
1032 K (759 °C)
Phase at STP
solid

Additional properties

Block
s-block
Electron configuration
[Ar] 4s¹
Electrons per shell
2, 8, 8, 1
Electronegativity
0.82
Density
0.862 g/cm³
Oxidation states
−1, +1 (a strongly basic oxide)
CAS Number
7440-09-7