← Periodic Table
37
s🧱
Rb
85.4680

Rubidium

Alkali Metal

Atomic Properties

Atomic Number
37
Atomic Mass
85.4680 u
Electron Configuration
[Kr] 5s1
Electronegativity
0.82
Block
s-block
Group
1
Period
5

🌡 Physical Properties

Phase (STP)
solid
Melting Point
312.45 K
Boiling Point
961.00 K
Density
1.5320 g/cm³

About Rubidium

Soft alkali metal; used in atomic clocks and specialized glass.

🔬 Isotopes of Rubidium

Rubidium has 2 naturally occurring isotopes.

IsotopeMass NumberAtomic Mass (u)AbundanceType
85Rb8584.9117897472.17%Stable
87Rb8786.9091805327.83%Stable

Data source: NIH PubChem (aggregated from IUPAC, NIST)