Atomic number 37
Rubidium
Alkali metal
In the real world
Quick facts
- Atomic mass
- 85.468
- Group
- 1
- Period
- 5
- State (STP)
- solid
- Electronegativity
- 0.82
- Common ox. states
- +1
Properties
Electron configuration
[Kr] 5s¹
- Ionization energy
- 403.0 kJ/mol
- Electron affinity
- 46.9 kJ/mol
- Melting point
- 312.45 K (39.3 °C)
- Boiling point
- 961.00 K (687.9 °C)
How dangerous is it?
5/5 · Extreme
One step below cesium in violence. It ignites the moment it meets air or water, so it lives sealed under inert gas.
- FlammableImmediate
Contact with moisture sets it alight immediately.
Kept far from water; fires are smothered with dry sand.
- ReactiveImmediate
It reacts explosively with water and catches fire in plain air.
Sealed in glass ampoules under argon; opened only inside a dry glovebox.
How it bonds
Rubidium follows the alkali-metal script: lose one electron, become Rb⁺. Even more reactive than potassium. Catches fire in air, explodes in water.
