## Help on how to find l, ml, and ms

1-D:

chrisdinkel_4E
Posts: 33
Joined: Fri Sep 28, 2018 12:17 am

### Help on how to find l, ml, and ms

Can someone please explain how to find these quantum numbers?

Tarika Gujral 1K
Posts: 62
Joined: Fri Sep 28, 2018 12:27 am

### Re: Help on how to find l, ml, and ms

l is angular momentum quantum number.
It is the number of subshells per principal energy level
l = n-1

ml is magnetic quantum number, and refers to the number of orbitals per subshell
ml = 2l + 1

ms is spin quantum number, and refers to spin of electron. It is either positive or negative one half

Posts: 77
Joined: Fri Sep 28, 2018 12:28 am
Been upvoted: 1 time

### Re: Help on how to find l, ml, and ms

The maximum value of l is n-1.
Ml is -l to l
and Ms is either +1/2 or -1/2, that's not something we can figure out.

For example, if N=2 then..
l can be 1 or 0
Ml's -1,0,1

Hope this helped!

Kim Tran 1J
Posts: 62
Joined: Fri Sep 28, 2018 12:24 am

### Re: Help on how to find l, ml, and ms

You will use n (principal quantum number) to find l. l will be a range of values starting from 0 up to n-1.
If n=3, l=0,1,2 (because from n-1, you know the last value l can be is 2)
If n=2, l=0,1

Once you know l, you will use l to find ml. ml= -l ,..., +l.
If l=0, ml=0
if l=1, ml= -1, 0, +1
if l=2, ml= -2, -1, 0, +1, +2

And ms = -1/2, +1/2. There are only two values that ms can be because there can only be two electrons in an orbital and each electron will spin in an opposite direction.

chrisdinkel_4E
Posts: 33
Joined: Fri Sep 28, 2018 12:17 am

### Re: Help on how to find l, ml, and ms

So, say for Ca, the quantum numbers would be:
n=4 (4th row)
l=0 (s block)
ml=0 (s block)
ms= -1/2 (2nd one of the s block)

Emily Li 4A
Posts: 24
Joined: Fri Sep 28, 2018 12:27 am

### Re: Help on how to find l, ml, and ms

This is a review I made while studying for my test:

>l is the orbital angular momentum quantum number
>this changes based on the block (s,p,d, or f)
>l=0 for the s block, 1 for the p block, 2 for d block, and 3 for f block

>n is the principle quantum number, or energy level
>increases in value by periods, going down
>starts at 1 for the s block, 3 for the d block, and 5 for the f block (you can tell this by how the f block is inserted into the d block, where the l value is 5)

>ml is the magnetic quantum number
>always 0 for s block
>halve each block, and number each half appropriately with negative numbers, 0, then positive numbers

>ms is magnetic spin
>starts positive at the left of each block, then turns negative, then positive...etc. until the end of the block

I highly suggest you look at a periodic table with all of the quantum numbers already labelled, as I found these trends and the locations of them on the table helped me greatly. At least, that's what I've done in high school; I've noticed others using equations to find the other numbers in a quantum number set, and those can be very helpful as well.

105085381
Posts: 44
Joined: Fri Sep 28, 2018 12:15 am

### Re: Help on how to find l, ml, and ms

SHELL --> n = 1,...,infinity
SUBSHELL --> l = {0,...,n-1}
ORIENTATION OF ORBITAL SPIN --> ml = {-l,...+l}
SPIN --> ms = {-1/2, +1/2}

These are the fundamental rules needed to determine sub-shell notation, electron configuration, valence electrons, unpaired electrons, etc.!