Now, to find a total number of orbitals in any given shell level with any given principal quantum number we simply take that principal quantum number and square it. So for N equals one there are one squared to one orbital. And that makes sense because when N equals one L equals zero and we have only the S orbital. For M equals two there are two squared to four total orbitals. And that also makes sense that we have the SPSP one and PZ a total of four orbitals. For M equals three, there are nine orbitals.