[fangrz]

Hi!

Could someone explain what this sentence means to me?

"Difference in electron-electron repulsion are responsible for the differences in energy between electrons in different orbitals in the same shell."

I understand that electrons in different shells (n=1, 2, 3...) have different energies, but I do not understand why a "p" orbital or an "s" orbital would have different energies. Furthermore, I don't understand how "electron-electron" repulsion relates to this. If you could point me to a website to read about this, I would greatly appreciate it.

Thank you.