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Quantum Number Definition

Chemistry Glossary Definition of Quantum Number

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Quantum numbers describe energy levels of atoms and molecules.

Quantum numbers describe energy levels of atoms and molecules.

Lawrence Lawry, Getty Images
Quantum Number Definition: A number used when describing the energy levels available to atoms and molecules. An electron in an atom or ion has four quantum numbers to describe its state.

There are four quantum numbers:

n - describes the energy level
ℓ - describes the subshell
m - describes the orbital of the subshell
ms - describes the spin

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