Azimuthal Quantum Number
The quantum number l that determines the shape of an orbital and the magnitude of the electron's orbital angular momentum.
Formula / equation
l = 0 to (n − 1)
Unit
Dimensionless
In depth
Also called the subsidiary or angular momentum quantum number, l labels the subshells s, p, d and f for values 0, 1, 2 and 3. Each subshell contains 2l + 1 orbitals. Within a shell, higher l means a less penetrating orbital that is more strongly shielded and so higher in energy in multi-electron atoms.
Examples in the real world
For n = 3, l can be 0 (3s), 1 (3p) or 2 (3d), giving one, three and five orbitals respectively.