Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Orbital angular momentum is a measure of the rotational motion of an electron around the nucleus in an atom. It is quantized and represented by quantum numbers.
5 Must Know Facts For Your Next Test
Orbital angular momentum is quantized and described using the azimuthal quantum number $l$.
The magnitude of orbital angular momentum is given by $\sqrt{l(l+1)}\hbar$, where $\hbar$ is the reduced Planck constant.
For a given principal quantum number $n$, the azimuthal quantum number $l$ ranges from 0 to $n-1$.
Each value of $l$ corresponds to a specific orbital shape (e.g., s, p, d, f orbitals).
The magnetic quantum number $m_l$, which ranges from $-l$ to $+l$, describes the orientation of the orbital angular momentum in space.
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Related terms
Azimuthal Quantum Number: A quantum number for an atomic orbital that determines its orbital angular momentum and describes its shape.
A quantum number denoted by $n$, indicating the relative size and energy level of an atomic orbital.
$m_l$ (Magnetic Quantum Number): A quantum number associated with each value of $l$, describing the orientation of an orbital’s angular momentum in space; it ranges from -$l$ to +$l$.