Pauli Exclusion Principle and Quantum Spin

[Azlyn Hernandez 2E]

The Pauli Exclusion Principle says that the spin quantum number must be +1/2 or -1/2 and that the two electrons in an orbital can't have the same spin. Is this a physical rule or just a way that we conceptualize and distinguish electrons?

[jayannkan2g]

Hi!

I think the reason why the spin states are 1/2 & -1/2 is because angular momentum is a vector, so it has a magnitude (1/2) and direction (+ or -). sinch each orbital can only hold two electrons, one electron will have a +1/2 spin and the other will have a -1/2 spin