Rubidium
Alkali Metal
Rubidium (Rb) is a chemical element with atomic number 37, classified as a alkali metal. At room temperature it is a solid. It was discovered in 1861 by Robert Bunsen, Gustav Kirchhoff.
Properties
- Atomic number
- 37
- Atomic mass
- 85.468 u
- Category
- Alkali Metal
- Group
- 1
- Period
- 5
- Block
- s-block
- Electron configuration
- [Kr] 5s¹
- Phase at STP
- Solid
- Density
- 1.532 g/cm³
- Melting point
- 312.46 K (39.3 °C)
- Boiling point
- 961 K (687.9 °C)
- Electronegativity
- 0.82
- Atomic radius
- 265 pm
- Ionization energy
- 4.177 eV
- Discovery
- 1861 · Robert Bunsen, Gustav Kirchhoff
Common uses
Atomic clocks, medical imaging, research, photocells
Did you know?
So reactive it ignites spontaneously in air and creates atomic clocks.
Experiment with the elements
Rubidium doesn't form any compounds in our lab yet, but the periodic table sandbox lets you combine dozens of other real elements into real compounds — water, table salt, ammonia and many more — with their true chemical formulas.