37Solid
Rb 85.468 Atomic mass · uAlkali metals
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.
Discovery 1861 (Robert Bunsen)
K2L8M18N8O1
Physical properties
Values for the element in its standard state.
- Density
- 1.532g/cm³
- Melting point
- 312K
- Boiling point
- 961K
- Atomic radius
- 211pm
- Bonding type
- Metallic
- Molar heat
- 31.06J/(mol·K)
Inside the atom
Electron arrangement and the energy behind its behavior.
Full electron configuration
1s, 2 electrons; 2s, 2 electrons; 2p, 6 electrons; 3s, 2 electrons; 3p, 6 electrons; 3d, 10 electrons; 4s, 2 electrons; 4p, 6 electrons; 5s, 1 electrons;
[Kr] represents 36 core electrons. The full view shows them explicitly.
37 electrons Orbital order preserved from source
- Electronegativity
- 0.82Pauling scale
- First ionization energy
- 403kJ/mol
- Electron affinity
- 47kJ/mol
- Van der Waals radius
- Not available
Rb RubidiumAtomic number 37
403kJ/mol
Atomic numberGaps indicate unavailable data
About rubidium
- Appearance
- Grey white
- Discovery
- 1861 (Robert Bunsen)
- Data source
- Read the reference
A missing value means it is unavailable in this reference dataset. Values can vary with measurement method and conditions.