Question about subshells and energy levels

[Vikram Sharma]

I had a question about something Lavelle talked about in lecture on Friday. He said that subshells on a certain energy level can have different energies relative to each other, such as the s orbital generally having a lower energy than p orbitals. Wouldn't this call for more energy levels? How can there be two subsheels with different energies on the same energy level? That doesn't make sense to me. Can someone explain?

[Reza Hemmati 3L]

Hi!

From what I understood from the lecture, in isolation, all subshells in the same energy level have the same energy. However, if you take into consideration the interactions that happen between the electrons(multi-electron system), this effectively changes the energies of each orbital. These interactions happen in the form of electron shielding, which pushes some orbitals out farther from the nucleus than others(including different orbitals in the same energy level). Since distance from the nucleus is associated with energy, this affects the energy of each orbital.

Hope this helps! ^^