Now let's look at the third quantum number. The third quantum number is called the magnetic quantum number. And this guy is designated by a lowercase M with a subscript L.
So ML for magnetic quantum number. The Magnetic Quantum Number designates the exact orbital in which our electron is in. Now recall that every subshell L has a certain amount of orbitals, right? When our M equals one, they were talking about the S orbital or L equals zero subshell.