## Confusion with n, l, ml, ms.

jonathanshi_1A
Posts: 22
Joined: Fri Jul 22, 2016 3:00 am

### Confusion with n, l, ml, ms.

On the midterm there was a question that asked how many elements have valence electrons with the quantum numbers n=2 and l=1. Looking on the table, there are 6 elements that fulfill that requirement; however, what if it said n=2 and l=0? Boron, carbon, nitrogen, oxygen, fluorine, and neon all have valence electrons with those quantum numbers, so would the answer be 2 elements or 8 elements?

Helena Vervaet 1N
Posts: 26
Joined: Wed Sep 21, 2016 2:59 pm

### Re: Confusion with n, l, ml, ms.

If the question states that n=2 and l=0, you would be looking at the s subshell of row 2. If we look at the periodic table, we can see that there are only 2 elements that fall in this specific subshell (lithium and beryllium) so your answer would then be 2.

Boron, carbon, nitrogen, oxygen, fluorine, and neon are all from the 2p subshell, so they would have a quantum number of l=1 instead of l=0 (0 corresponds with s and 1 corresponds with p). I hope this helped!

Pauline Tze 3B
Posts: 57
Joined: Sat Jul 09, 2016 3:00 am
Been upvoted: 1 time

### Re: Confusion with n, l, ml, ms.

Hello,

I'm also stuck on this concept. If it said n=2 and l=0, there's the possibility of boron, carbon, nitrogen, oxygen, fluorine, and neon all have valence electrons with those quantum numbers because, for example, the valence electron configuration of Boron is [He]2s22p1. The 2s orbital would have l=0 as its quantum number, so doesn't that mean Boron (and the other 2p elements in that row) counts as one of the elements with n=2 l=0?

Thank you to anyone who can clarify this.