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Rubidium (Rb) – Element 37 of the periodic table

Rubidium (symbol Rb) is element number 37 of the periodic table and belongs to the “Alkali metal” category. Its atomic mass is about 85.468, and its phase under standard conditions is Solid. This element sits in period 5 and group 1 of the periodic table, and its electrons are arranged in shells of 2, 8, 18, 8, 1. The short electron configuration of Rubidium is [Kr] 5s¹. Known uses of Rubidium include Atomic clocks, Photoelectric cells and Medical research.

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Properties of Rubidium

Atomic number
37
Chemical symbol
Rb
Atomic mass
85.468
Category
Alkali metal
Period
5
Group
1
Phase
Solid
Protons
37
Electrons
37
Neutrons (approx.)
48
Electron shells
2, 8, 18, 8, 1
Outer-shell electrons
1
Discovered
Robert Bunsen (1861)

Electron configuration of Rubidium

The electron configuration of Rubidium (Rb), with 37 electrons, is shown below. The last shell (shell 5) is highlighted:

Full configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹
Short configuration
[Kr] 5s¹
Last shell
5s¹

What is electron configuration and how is it written?

Electron shells of Rubidium

Distribution of 37 electrons of Rubidium across shells K to O:

  1. K2
  2. L8
  3. M18
  4. N8
  5. O1

What is a alkali metal?

The alkali metals are the group 1 elements (excluding hydrogen): soft, shiny and highly reactive metals that react violently with water and are never found free in nature.

Uses of Rubidium

Frequently asked questions about Rubidium

What is the atomic number of Rubidium?

The atomic number of Rubidium (Rb) is 37; that is, every atom of it has 37 protons.

What is the electron configuration of Rubidium?

The electron configuration of Rubidium (Rb) is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹; in short form it is [Kr] 5s¹, and its last shell is 5s¹.

What is the chemical symbol of Rubidium?

The chemical symbol of Rubidium is Rb.

Where is Rubidium located in the periodic table?

Rubidium is located in period 5 and group 1 and belongs to the “Alkali metal” category.

What is the atomic mass of Rubidium?

The atomic mass of Rubidium is about 85.468 (atomic mass units).

What is the phase of Rubidium under normal conditions?

The phase of Rubidium under standard conditions is Solid.

What are the uses of Rubidium?

Uses of Rubidium include Atomic clocks, Photoelectric cells and Medical research.

Who discovered Rubidium?

Rubidium was discovered by Robert Bunsen in 1861.

Elements in the same category as Rubidium (Alkali metal)

Lithium (Li)Sodium (Na)Potassium (K)Cesium (Cs)Francium (Fr)

See all Alkali metals

Rubidium’s group 1 neighbours

Hydrogen (H)Lithium (Li)Sodium (Na)Potassium (K)Cesium (Cs)Francium (Fr)

Group 1 of the periodic table