Rubidium (Rb)
Rubidium (Rb, element 37) is an alkali metal in group 1, period 5. Atomic mass 85.468, electron configuration [Kr] 5s¹, uses and facts.
About Rubidium
Rubidium is an alkali metal with the symbol Rb and atomic number 37. It is a solid at room temperature, and it sits in group 1, period 5 of the periodic table. Rubidium was discovered in 1861 by Robert Bunsen.
Rubidium key facts
- Atomic number: 37
- Symbol: Rb
- Atomic mass: 85.468 u
- Category: alkali metal
- Group: 1
- Period: 5
- State at room temperature: solid
- Electron configuration: [Kr] 5s¹
- Electronegativity (Pauling): 0.82
- Melting point: 312.45 K (39.3 °C)
- Boiling point: 961 K (687.85 °C)
- Density: 1.532 g/cm³
- Common oxidation states: −1, +1
Electron configuration
The electron configuration of rubidium is [Kr] 5s¹. The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Rubidium has 1 valence electron.
Uses of rubidium
- Atomic clocks
- Fireworks (violet color)
- Research
Did you know?
Rubidium clocks are so precise they lose only 1 second every 300 years.
Other elements in group 1 and neighbours
Frequently asked questions
What is the atomic number of rubidium?
The atomic number of rubidium is 37, which means every rubidium atom has 37 protons.
What is the electron configuration of rubidium?
The electron configuration of rubidium is [Kr] 5s¹.
What group and period is rubidium in?
Rubidium is an alkali metal in group 1, period 5.
What state is rubidium at room temperature?
Rubidium is a solid at room temperature.
What is rubidium used for?
Rubidium is used for atomic clocks, fireworks (violet color), research.