37
Rb
rubidium
85.468

General properties

Group
group 1 (H and alkali metals)
Period
period 5
Category
alkali metals
Standard atomic weight
85.4678(3)
Melting point
312.45 K (39.30 °C)
Boiling point
961 K (688 °C)
Phase at STP
solid

Additional properties

Block
s-block
Electron configuration
[Kr] 5s¹
Electrons per shell
2, 8, 18, 8, 1
Electronegativity
0.82
Density
1.532 g/cm³
Oxidation states
−1, +1 (a strongly basic oxide)
CAS Number
7440-17-7