Spin Quantum Number

[Doreen Liu 4D]

I know that the spin quantum (ms) describes the angular momentum of an electron, but I am confused on when to use that number +1/2 and -1/2 or is it only for drawing the arrows?

[Parker Smith]

the +1/2 and the -1/2 are used to signify the spin of the electron. So if you are only drawing the arrows, you probably don't need to use the ms numbers because the arrows signify spin direction already. It depends on what the problem asks of you.

[Michelle Le 1J]

The four quantum numbers altogether help to completely describe an electron in an atom and its spin state, thus you would use that number to specify the spin state of a certain electron.

[KBELTRAMI_1E]

the +1/2 and the -1/2 are used to signify the spin of the electron. So if you are only drawing the arrows, you probably don't need to use the ms numbers because the arrows signify spin direction already. It depends on what the problem asks of you.

how do you know which direction it goes though?

[Daria Azizad 1K]

We generally say that the first electron is up and the second is down. We can only determine spin experimentally and therefore just need to know theoretically what the spin would be (based on what we know about electron repulsion).

[Kassidy Ford 1I]

It is also good to know that when electrons are paired, they have opposite spins. when electrons are unpaired but in the same orbital, they have parallel spins

[Maddie]

It also doesn't matter when your drawing out the configuration as long as you're consistent whether or not you have them spinning down or up every time