I have already turned in my homework for chemistry however I'm still confused about this question: Which electron configuration is in an excited state? a.1s2 2s2 2px2 b.1s2 2s1 2px1 2py1 2pz1 My teacher told me that the only choice b was excited because choice a was in violation of Hund's rule. I am confused because I thought both of these choices were in violation of Hund's rule, and I'm not sure what the difference is. I know that choice a has an iccorect filling order because for 2px to have 2 electrons both 2py and 2pz would need 1 e-. Also I know that choice b has an incorrect filling order because the 2s needs to be filled before p can have any e-. So I thought both a and b would excited bacause they had electrons in the wrong places. Any and all help with this will be greatly appreciated.