37 Rb 85.468

Rubidium

alkali metal

Properties

Atomic number
37
Atomic mass
85.468 u
Category
alkali metal
Group
1
Period
5
Block
s-block
State (room temp)
Solid
Outer-shell electrons
1
Electronegativity
0.82 (Pauling)
Density
1.532 g/cm³
Melting point
39.3 °C
Boiling point
687.85 °C

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹

Noble-gas shorthand: [Kr] 5s¹

Electrons per shell: 2, 8, 18, 8, 1 — that's 1 in the outermost shell.

See how electron configuration is built →

Rb
Bohr model — outer-shell electrons in blue

About Rubidium

Rubidium is a chemical element with symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group, with an atomic mass of 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, such as very rapid oxidation in air.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.