Magnetic Spin Quantum Number [ENDORSED]

[Jonathan Alterman 1C]

Hi! Can somebody please explain to me how to determine the magnetic spin (Ms) quantum # of an electron? I understand that it would be -½ or ½, but how do we decide which one it is?

[Riya 14B-2]

Hey!

Not sure if this is what you mean, but since there can only be 2 electrons in each orbital, one will be +1/2 and the other will be -1/2, having opposite spins. So, the Ms quantum number of an atom is based upon the spin of last electron to enter. Because electrons enter orbitals singly before pairing, if the last electron in the atom occupies its own orbital (is unpaired) then Ms is +1/2, whereas if the last electron in the atom is a paired electron, then Ms is -1/2.

Hope this sorta helps :)

[Nathaniel John 2E]

Hello! For the magnetic spin quantum number, I'm pretty sure that it doesn't matter which electron you make +1/2 or -1/2. However, generally the first unpaired electron in each orbital is usually assigned the +1/2 magnetic spin value.

Hope this helps!

[Martha Avila 1I]

Hello. Another helpful trick that I learned in the step-up sessions was that spin up and spin down correspond to an ms value. For example if in a question you are told that there is a spin up then you know your value will be +1/2 and if it is spin down then your value will be -1/2. I am not too sure if this is how it works 100% of the time but I hope this helped a little.