## 1D.23 Homework Question

Fiona Latifi 1A
Posts: 102
Joined: Sat Sep 14, 2019 12:16 am

### 1D.23 Homework Question

1D.23 How many orbitals can have the following quantum numbers in an atom?
(a)n=2, l=1
(b)n=4, l=2, ml=-2
(c)n=2
(d)n=3, l=2, ml=+1

I understand that the answer to B and D is 1 because they both have 3 quantum numbers that identify a single orbital. Could someone please explain how the answer to A is 3 and the answer to C is 4? Thanks!

Deepika Reddy 1A
Posts: 125
Joined: Thu Jul 11, 2019 12:15 am

### Re: 1D.23 Homework Question

For a, n=2 tells you that we are looking at the second shell. And then l = 1 means that we are looking at a p orbital. However, the magnetic quantum number is not specified so we do not know which orientation of the p orbital it is. This means that it could be any of the three p orbitals. Therefore, three orbitals can have these quantum numbers.
For c, it only says that n=2 which means all we know is that we are looking at the second shell. In the second shell, we have one s orbital and 3 p orbitals. Therefore, four orbitals can have this quantum number.