Question

Which of the following sets of quantum numbers is not possible?

• A. $n=1,l=0,\,{{m}_{1}}=0,{{m}_{s}}=-\frac{1}{2}$
• B. $n=1,l=1,\,{{m}_{1}}=0,{{m}_{s}}=+\frac{1}{2}$
• C. $n=2,l=1,\,{{m}_{1}}=0,{{m}_{s}}=+\frac{1}{2}$
• D. $n=3,l=1,\,{{m}_{1}}=0,{{m}_{s}}=+\frac{1}{2}$

Answer 1

Answer: (B)

$n=1,l=1,\,{{m}_{1}}=0,{{m}_{s}}=+\frac{1}{2}$

Answer 2

The set of quantum numbers $n =1, l =1, m _{ l }=0, m _{ s }=+\frac{1}{2}$ is not possible for
an electron.
When $n =1,1$ can have a maximum value of o. It cannot be $1 .$
For a given value of $n$, the possible values of 1 are $0,1,2, \ldots,( n -1)$.