Take the 2-minute tour ×
Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers and students. It's 100% free, no registration required.

According to Pauli’s exclusion principle, an $s$ orbital contains at most two electrons with the opposite spin (up and down). Why can't an $s$ orbital contain a third electron whose state is the linear combination of spin up and down?

share|improve this question
Rhys gives a good answer here: physics.stackexchange.com/questions/44602/… –  hlew Nov 20 '12 at 8:13

1 Answer 1

Because we can have only one electron per quantum state. Spin up and spin down are two different states. A linear combination of the two is not a new independent state. It is obviously formed from the spin up and spin down states.

share|improve this answer
-1. First, it does not answer the question, it just paraphrases it in a different way. Secondly, it is just plain wrong. A linear combination of two states is a new state, this new state is obviously linearly dependent with the two states, but it is a different state. –  Wildcat Jan 19 at 9:59

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.