The angular momentum quantum number, often denoted by the symbol “l,” is one of the quantum numbers used to describe the properties of an electron in an atom. It is part of the quantum mechanical model and helps specify the shape of the electron’s orbital.
The angular momentum quantum number can have integer values ranging from 0 to (n-1), where “n” is the principal quantum number. Therefore, if the principal quantum number (n) is, for example, 3, then the possible values for l are 0, 1, and 2.
The value of “l” determines the shape of the orbital. Each value of “l” corresponds to a different type of orbital, such as s, p, d, or f orbitals.
The angular momentum quantum number is related to the sublevels within a principal energy level. For example, in the first energy level (n = 1), there is only one sublevel (l = 0), which corresponds to an s orbital.
If “n” is 3, then the possible values for “l” are 0, 1, and 2. This means there are s, p, and d orbitals in the third energy level.
| Orbital Type | Corresponding “l” Value |
|---|---|
| s orbital | 0 |
| p orbitals | 1 |
| d orbitals | 2 |
| f orbitals | 3 |
Examples
| Atom | Principal Quantum Number (n) | Possible Angular Momentum Quantum Numbers (l) | Corresponding Orbital Types |
|---|---|---|---|
| Hydrogen (H) | 1 | 0 | s |
| Helium (He) | 1 | 0 | s |
| Lithium (Li) | 2 | 0, 1 | s, p |
| Oxygen (O) | 2 | 0, 1 | s, p |
| Sodium (Na) | 3 | 0, 1, 2 | s, p, d |
| Chlorine (Cl) | 3 | 0, 1, 2 | s, p, d |
| Iron (Fe) | 4 | 0, 1, 2, 3 | s, p, d, f |
