## 2.29 parts b and d

sofiakavanaugh
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am
Been upvoted: 1 time

### 2.29 parts b and d

How many electrons can have the following quantum numbers:
b) n=4, l=2, ml=-2
d) n=3, l=2, ml=+1

Can someone please explain why the answer is 2 for both of them? The part I don't understand really is M(l).

Thanks!

Posts: 60
Joined: Sat Jul 22, 2017 3:00 am
Been upvoted: 1 time

### Re: 2.29 parts b and d

Each orbital in every subshell can hold at the most two electrons. The magnetic quantum number (ml) specifies a specific orbital within a subshell, and can have a value of -l <= ml <= +l. For example, within the p orbital (l=1) are the subshells ml= -1, 0, +1. In the given textbook problems, each value of ml is specifyng a particular orbital in the d subshell. However, because no magnetic spin quantum number (ms, +1/2 or -1/2) has been specified, there are two electrons that could have the given quantum numbers.

104922499 1F
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### Re: 2.29 parts b and d

Whenever I do questions like this I make this table to remind me of the of the l #, orbital, and electron amount

l= orbital e-
0 s 2
1 p 6
2 d 10
3 f 14

so for b) because l=2, this problem has 2e-
same for part d because l=2

Clarissa Molina 1D
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

### Re: 2.29 parts b and d

I am still a little confused, how do you determine how many electrons can have certain quantum numbers?
In 2.29a with the quantum numbers n=2 and l=1, the answer is 6 electrons, but why is that the answer?

Posts: 60
Joined: Sat Jul 22, 2017 3:00 am
Been upvoted: 1 time

### Re: 2.29 parts b and d

The right-most number in the previous user's table displays the maximum number of electrons that specific subshell can accommodate. In your question, the quantum numbers n=2 and l=1 tell us that we are looking at a 2p subshell. However, we do NOT know the orbital number (ml) or the spin number (ms), so we can just consider all possibilities for now. There are 6 electrons maximum that can exist within the 2p subshell; therefore, that is your answer.