## quantum number 4

Isaias Gomez D3A
Posts: 67
Joined: Wed Sep 30, 2020 9:37 pm
Been upvoted: 1 time

### quantum number 4

Hi! So, I understand that the fourth quantum number gives us the spin of the electron in the outer shell, and I understand why no two electrons in the same atom can have the same 4 quantum numbers, but what I don't understand is why the knowing the 4th quantum number is useful in any way. Is there something we can gain by knowing all 4 quantum numbers other than just being able to give its spin direction?

Posts: 115
Joined: Wed Sep 30, 2020 10:01 pm
Been upvoted: 2 times

### Re: quantum number 4

Two electrons must be in opposite spins in one orbital. By knowing the spins and the number of electrons in an orbital (whether the orbital has paired or unpaired electrons), we can determine if there is a magnetic field.

clairehathaway 2J
Posts: 76
Joined: Wed Sep 30, 2020 9:38 pm

### Re: quantum number 4

I think that knowing the 4th quantum number can be beneficial because then we are able to differentiate completely between each electron. If we only had the first 3 quantum numbers there would often be 2 electrons that shared all 3 values but by identifying the 4th each electron has its own set of numbers. Essentially, by having all 4 quantum numbers (instead of 3) we are able to completely specify an electron in an atom.

Shrinidhy Srinivas 3L
Posts: 85
Joined: Wed Sep 30, 2020 9:39 pm
Been upvoted: 2 times

### Re: quantum number 4

The 4th quantum number shows us the spin of the electron. Using the 4th quantum number, we can determine the magnetic field of the electron and it shows us which "way" the electron is going, to put it simply.

Mackenzie Stockton 2H
Posts: 69
Joined: Wed Sep 30, 2020 10:11 pm

### Re: quantum number 4

I think the biggest reason for knowing the fourth quantum number is to understand that no 2 electrons can have the same 4 quantum numbers in an atom. The fourth quantum number provides the direction of spin.

Kelly Tran 1J
Posts: 111
Joined: Wed Sep 30, 2020 9:50 pm
Been upvoted: 1 time

### Re: quantum number 4

Knowing the 4th quantum number is not only important because it tells you the electron's spin direction, but it also specifies the electron. While 2 electrons can have the same first 3 quantum numbers, no 2 electrons can have the same 4th quantum number as the spin states can either be spin up or spin down. This means that if 2 electrons are in the same state (have the same first 3 quantum numbers), they must have opposite spin, which reinforces the Pauli Exclusion Principle.

Evie Li_1H
Posts: 69
Joined: Wed Sep 30, 2020 9:48 pm
Been upvoted: 1 time

### Re: quantum number 4

Also if the question is asking how many electrons can have "this" electron configuration (there was one problem like this in the sapling) and it goes so far to specify the orbital up to the fourth quantum number, ml, then the answer would automatically be 2 because any subshell can only hold a maximum of 2 electrons each, and identifying all quantum numbers will leave you with one particular shell.