## Quantum Numbers

Matia Kim 1B
Posts: 60
Joined: Fri Apr 06, 2018 11:03 am

### Quantum Numbers

How do you know if the charge is positive 1/2 or negative 1/2?

Chloe Qiao 4C
Posts: 65
Joined: Fri Sep 28, 2018 12:27 am

### Re: Quantum Numbers

If you mean the magnetic spin quantum number, +1/2 is for the anti-clockwise rotation and -1/2 is for the clockwise rotation.

Kessandra Ng 1K
Posts: 67
Joined: Fri Sep 28, 2018 12:25 am

### Re: Quantum Numbers

I don't think you would need to know exactly which electron is +1/2 or -1/2; just know that the electrons in the same sub-shell must have opposite spin so one of them must be +1/2 and the other -1/2.

Michael Torres 4I
Posts: 92
Joined: Thu May 10, 2018 3:00 am
Been upvoted: 1 time

### Re: Quantum Numbers

In addition to what others have said I also recommend taking into consideration Hund's Rule and the electron configuration exceptions Lavelle mentioned (Cr and Cu) whenever asked anything about electron spin even if you may not know the specific spin of an electron in an orbital.

Alexandra Albers 1D
Posts: 61
Joined: Fri Sep 28, 2018 12:18 am

### Re: Quantum Numbers

As of yet, we haven't needed to know how to determine the spin of a specific electron. We do know that in the configuration, electrons should be organized with parallel spins first though and then have the electrons of opposing spins added afterwards.

Manya Kidambi 3I
Posts: 31
Joined: Fri Sep 28, 2018 12:24 am

### Re: Quantum Numbers

You would have to draw out the orbital diagram. If the arrow is pointing up, it is +1/2 and if it is pointing down it is -1/2.