37 Rb Rubidium 85.468 u

Rubidium

Period
5
Group
1
Block
s-block
Phase (STP)
Solid

Rubidium is a soft, silvery-white alkali metal that ignites spontaneously in air. It is used in atomic clocks and specialty glass.

About Rubidium

Soft, silvery-white, and reactive enough to ignite spontaneously in air, rubidium is an alkali metal of atomic number 37 and atomic mass 85.468. Its single valence electron ([Kr] 5s1) is loosely bound, giving the low electronegativity of 0.82 characteristic of its group. The element is a solid under standard conditions and sits in group 1, period 5, below potassium. As a heavier member of the alkali metals, rubidium holds its outer electron more weakly and is correspondingly more reactive than the lighter members, and it is never found in the free state. Its specialized uses include atomic clocks and the manufacture of certain specialty glasses, applications that draw on its well-defined atomic transitions and ready ionization.

Physical Properties

Atomic Mass 85.468 u
Phase at STP Solid

Electronic Properties

Electronegativity 0.82

Electron Configuration

Configuration [Kr] 5s¹

Electron Shell Configuration

Rubidium electron shell configuration Rb 2e⁻ 8e⁻ 18e⁻ 8e⁻ 1e⁻
Electron shell structure of Rubidium — electrons per shell.
Shell Electrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) 8
5 (O) 1

Position in Periodic Table

Rubidium position in the periodic table Rb

Block & Period

Block

s p d f

Period

1 2 3 4 5 6 7

Periodic Table

Lanthanides Actinides

More Alkali Metal

3 Li Lithium 11 Na Sodium 19 K Potassium 55 Cs Cesium 87 Fr Francium

Frequently Asked Questions

What is Rubidium?
Rubidium (Rb) is a chemical element with atomic number 37. It is a solid at standard temperature and pressure, classified as a alkali metal.
What are the key properties of Rubidium?
Rubidium has an atomic mass of 85.468 u.
What is the electron configuration of Rubidium?
The electron configuration of Rubidium is [Kr] 5s1. It is in the s-block of the periodic table.
What is the electronegativity of Rubidium?
Rubidium has an electronegativity of 0.82 on the Pauling scale.