## Spin Quantum Number Question

Vincent Chiang 1L
Posts: 54
Joined: Fri Sep 29, 2017 7:05 am

### Spin Quantum Number Question

The following question was presented:

"Copper is an interesting element as it has 10 elections in its 3d subshell and only one in its 4s subshell. What are the quantum numbers (n and l) that are associated with this last 3d^10 electron? Also, write all the possible values that a spin quantum number can take for this electron."

The answer to m(s) was +/- 1/2, but I only got - 1/2... can someone explain why positive 1/2 is correct too?

Hannah Chew 2A
Posts: 76
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 2 times

### Re: Spin Quantum Number Question

An electron can have either spin value, ms = -1/2 or 1/2. Since 3d9 and 3d10 are in the same orbital, they must have opposite spin. It could be either 1) 3d9 is -1/2 and 3d10 is 1/2 or 2) 3d9 is 1/2 and 3d10 is -1/2. So therefore, 3d10 can have either spin number if 3d9’s spin number is not specified.

Leah Thomas 2E
Posts: 51
Joined: Fri Sep 29, 2017 7:06 am

### Re: Spin Quantum Number Question

You might have also been confused because usually the positive spin of the electron is drawn first and then the negative spin when filling the orbital but the 3d10 electron can still have either spin since you don't know specifically the electron that is filling that last d orbital.