## Fourth Quantum Number

Rebekah Kaufman 1L
Posts: 25
Joined: Fri Apr 06, 2018 11:03 am
Been upvoted: 1 time

### Fourth Quantum Number

Do we always need to calculate the fourth quantum number or do we only need to specify it if specifically asked?

Jocelyn Fermin1J
Posts: 49
Joined: Tue Nov 14, 2017 3:01 am

### Re: Fourth Quantum Number

I think if the question specifically asks, but its pretty staight forward; it's just asking if the electron spin is up or down.

Brynne Keyser 1B
Posts: 31
Joined: Fri Apr 06, 2018 11:03 am

### Re: Fourth Quantum Number

The fourth quantum number is used to indicate the orientation of the two electrons in each orbital. The values for ms are +1/2 and -1/2. An atom is the most stable when its electrons have the lowest possible energy.

I think that you will be able to determine what the fourth quantum number is based off of the other quantum numbers.

Susu Le 1F
Posts: 30
Joined: Thu Feb 01, 2018 3:01 am
Been upvoted: 1 time

### Re: Fourth Quantum Number

I am confused on how we would determine if an electron is spinning up or down?

Emma Leshan 1B
Posts: 30
Joined: Fri Apr 06, 2018 11:03 am

### Re: Fourth Quantum Number

I don't think you necessarily need to calculate whether the spin is up or down, you just need to know that if there are 2 electrons occupying the same orbital, one will spin up and one down.

Jasmine Emtage-1J
Posts: 24
Joined: Fri Apr 06, 2018 11:02 am

### Re: Fourth Quantum Number

I'm not sure if we actually need to calculate whether the electron is spinning up or down but if you're given the ms value of +1/2 you should know that it means the electron is spinning up and if you're given the ms value -1/2 you should know that the electron is spinning down.