My understanding of the angular momentum quantum number is that a different number indicates a different region of space that the electron can occupy. So does the principle quantum number determine the size of that region? For example, is 2s the same as 3s in shape, but the 3s has a greater radius? Also can different orbitals such as the s and p orbitals overlap? If so, would the energy levels in the overlapping regions be the same? I'm having a hard time picturing the meaning of the quantum numbers.