Answer:
(a) "l" cant be more than n-1. n= 3 so l cant be more than 2.
(b) Valid
(c) If l=0, ml can only be 0.
Sb, Antimony, 51 electrons
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3
paramagnetic 3 unpaired electrons
Explanation:
(a) "l" (lower case L) can be 0, 1, 2 up to n-1. If n=3, l can be 0, 1, or 2.
(b) This set of quantum numbers is valid. n can be 1, 2, 3, ...
since n= 2, l can be any number from 0 to n-1 or 0,1
Since l=1, ml can be -1, 0, 1
ms can always be +1/2 or -1/2
(c) ml can only be from -l to +l. If l=0, ml=0.
If l was 2, ml could be -2, -1, 0, 1, 2
