## Quantum Numbers

eduardomorales5
Posts: 77
Joined: Fri Aug 30, 2019 12:15 am

### Quantum Numbers

How do we know when to put the spin number? How does an electron's spin affect its behavior?

Sarah Blake-2I
Posts: 153
Joined: Fri Aug 30, 2019 12:16 am

### Re: Quantum Numbers

You put the spin number when you are discussing the state of both the electron and the orbital and then just 3 quantum numbers when just discussing the state of the orbital.

Rohit Ghosh 4F
Posts: 99
Joined: Thu Jul 25, 2019 12:17 am

### Re: Quantum Numbers

The spin number is usually either +1/2 or -1/2, denoting whether the electron is "spin-up" or "spin-down." Electrons spinning in different directions are often paired together in a subshell.

905385366
Posts: 54
Joined: Sat Jul 20, 2019 12:16 am

### Re: Quantum Numbers

The spin would be denoted with the 4th Quantum number (+/- 1/2). Another tip is to remember to use the Pauli Exclusion Principal and Hund's Rule when drawing it out. Hope that helps.

kristi le 2F
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

### Re: Quantum Numbers

Also, no two electrons can have the same four quantum numbers. If two electrons share the first three quantum numbers (n, l, ml), their spins must be different. One will be +1/2 while the other will be -1/2.

PGao_1B
Posts: 50
Joined: Sat Jul 20, 2019 12:15 am

### Re: Quantum Numbers

Electron spin, s, has only two possible values: and , representing whether the electron is "spin - up" or "spin - down," respectively. Electron spin determines if an atom will or will not generate a magnetic field.

505306205
Posts: 97
Joined: Thu Jul 25, 2019 12:15 am

### Re: Quantum Numbers

Electron spins affect an electron's behavior because it prevents two electrons with parallel spins from occupying the same orbital. The configuration is most stable when electrons are paired with electrons with opposite spins.

Eva Zhao 4I
Posts: 101
Joined: Sun Sep 29, 2019 12:16 am

### Re: Quantum Numbers

The spin number, or the spin magnetic quantum number (ms), is +1/2 or -1/2 since an electron can be spin up or down. The significance is that no two electrons in the same atom can have the same four quantum numbers. It tends to be pretty arbitrary as long as the combination of the four quantum numbers is possible; the principle quantum (n) and angular momentum quantum (l) numbers are typically the definite ones.