Energy Levels

[Nithya Narapa Reddy]

On Friday it was mentioned that subshells that are on the same energy level can have different energies. I don't realize that was possible because I thought that everything on the same energy level had the same energies as each other. Can someone please explain how this works?

[Warren Jolicoeur 1B]

I could be wrong but I think he's talking about P vs S vs D subshells. although 3 P and 3 S are on the same "energy level". They have different energies. We can see this in D block the best. Lets take element Element 31. Gallium for example. It's Quantum Numbers would be something like [Ar]: 4S², 3D¹⁰ 4p¹. If all subshells had the same energy, then it there would not be a 3D separating 4s and 4p. Correct me if I'm wrong but that's how I think it works. Their orbitals determine the energy.

[MattDixon3A]

Hi, in general I believe that the simplified answer to your question is yes, every orbital in the same electron shell has the same energy. This is just an approximation though, as various properties such as magnetic fields create small energy differences between energy levels. I hope this helps clarify a bit!