Rubidium (Rb)
Rubidium
Rubidium (Rb) is an alkali metal in period 5, group 1. Its relative atomic mass is 85.468 and the molar mass of the atom is 85.468 g/mol.
Atomic number 37
Atomic mass 85.468
Molar mass 85.468 g/mol
Category Alkali metal Solid
Properties of rubidium
| Atomic number | 37 |
|---|---|
| Symbol | Rb |
| Latin name | Rubidium |
| Relative atomic mass | 85.468 |
| Molar mass | 85.468 g/mol |
| Group, period, block | 1, 5, s |
| Category | Alkali metal |
| State at 20 °C | Solid |
| Electron configuration | [Kr] 5s¹ |
| Electronegativity (Pauling) | 0.82 |
| Atomic radius | 235 pm |
Electron configuration of rubidium
Electrons per shell
K2L8M18N8O1
Full notation
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹
Noble-gas notation
37 protons · 37 electrons[Kr] 5s¹
Formula and compounds of rubidium
Simple substanceRbrubidiumMolar mass of Rb: 85.468 g/mol
Chemistry not clicking? Try a lesson with a tutor
1-to-1 online chemistry lessons for KS3, GCSE and A-level. Your first lesson is a free trial.
Frequently asked questions
The relative atomic mass of rubidium is 85.468, so the molar mass of the atom is 85.468 g/mol.
Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹. Noble-gas notation: [Kr] 5s¹.