Question

Which set of quantum numbers are not possible?
n l m s
(a) 3 2 0 +1/2
(b) 2 2 1 +1/2
(c) 1 0 0 –1/2
(d) 3 2 –2 +1/2

Answer 1

The set of quantum numbers not possible

is option (b)

1) Here given is n=2 l=2 m=1 s= +1/2

2) We know value of n can be n=0,1,2,3...

And value of m is m=n-1

But here m=n which not possible.

3) similarly l lies between -m to +m

4) and s can be +1/2 or -1/2

Answer 2

The set of quantum numbers which are not possible is (b) 2 2 1 +1/2

1. Principal Quantum number n have possible values 1,2,3,4....
2. Angular Momentum Quantum number l have possible values 0,1,2,3,....,(n-1)
3. Magnetic Quantum number m have possible values -l,...,-1,0,1,....,l
4. Spin Quantum number s have possible values +1/2,-1/2\
5. So in option b n=2 and l=2 which is not possible because l have n-1 value so correct l for n=2 is 1 but it is given as 2.