Second Quantum Number Definition

The second quantum number describes the shape of an electron's orbit.
The second quantum number describes the shape of an electron's orbit. PASIEKA / Getty Images

Second Quantum Number Definition: The second quantum number, ℓ, is the quantum number associated with the angular momentum of an atomic electron. The second quantum number determines the shape of the electron's orbital.

Also Known As: azimuthal quantum number, angular momentum quantum number

Examples: A p orbital is associated with a second quantum number equal to 1.