[djvan]

I'm reviewing quantum numbers, and have a question about the 3rd quantum number, m_l.  If m_l represents the specific orbital of an electron, why isn't the sum of the number of integers from -l to l equal to n², where n² is the number of orbitals.

For instance: let's describe an electron in a p orbital.  n=2, l=1, m_l= ^-1, 0, or 1, and m_s = -0.5 or 0.5.

My question is, why isn't the sum of the number of possible integers for the value of m_l (in this case 3) not equal to the total number of orbitals (which is n², which in this case is 4)

Is there an orbital which an electron cannot occupy?

Ah- I just answered my own question.  The second quantum number specifies the subshell, hence the orbitals from s subshell are ignored in the 3rd quantum number.  Posting this anyway, perhaps it will help someone else.