Symbol
Rb
Atomic Number
37
Atomic Mass
85.468
Protons
37
Neutrons
48
Electrons
37
Type
Alkali Metal
Isotopes
Rubidium-85, Rubidium-87
Discovery Year
1861
Discovered By
Robert Bunsen, Gustav Kirchhoff
Group
1
Period
5
Boiling Point
1510°F
Melting Point
39.3°F
Electron Configuration
[Kr] 5s¹
Density (g/cm³)
1.532
Crystal Structure
Body-centered cubic
Magnetism
Paramagnetic
Abundance in Earth's Crust
0.00035%
Phase at Room Temperature
Solid