Hi everyone I'm currently studying the MO theory and ran into some trouble understanding orbital energy levels. As I have previously read, σ bonds are stronger than ∏ bonds, therefore are lower in orbital energy. However, from the MO theory, the σ2p orbital is actually higher in energy than the ∏2p orbital in molecules like B2 and N2. But in molecules like O2 and F2, this sequence is reversed, with the ∏2p orbital having the higher orbital energy. Can anyone tell me why?