Rubidium (symbol Rb, atomic number 37) is a soft alkali metal used in atomic clocks and specialty glass. It is classified as a alkali metal and sits in group 1, period 5 of the periodic table.
Overview
Rubidium is the chemical element with atomic number 37 and the symbol Rb. With a standard atomic weight of 85.468, it is a alkali metal. In the periodic table it occupies group 1 and period 5, and under standard conditions it is normally a solid. Rubidium is a soft alkali metal used in atomic clocks and specialty glass.
Atomic structure
An atom of Rubidium has 37 protons in its nucleus and, when neutral, 37 electrons arranged in the configuration [Kr] 5s1. Its standard atomic weight of 85.468 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Rubidium was discovered in 1861 by Robert Bunsen, Gustav Kirchhoff. It follows Krypton (Kr) and precedes Strontium (Sr) in order of atomic number.
| Atomic number | 37 |
|---|---|
| Symbol | Rb |
| Atomic mass | 85.468 |
| Category | Alkali metal |
| Group | 1 |
| Period | 5 |
| Electron configuration | [Kr] 5s1 |
| Phase at STP | Solid |
| Discovered | 1861 (Robert Bunsen, Gustav Kirchhoff) |