Question

In an atom, the total number of electrons with quantum numbers $n=5,l=2,ands=-\frac{1}{2}$

• A.
  5
• B.
  10
• C.
  3
• D.
  4

Answer 1

The correct option is A

5
$n=5,l=2,ands=-\frac{1}{2}$

The above quantum numbers is the description of 5d subshell with spin $s=-\frac{1}{2}$. Number of orbitals in a d subshell with l = 2 is $2l+1$ = $2\times 2+1$ = 5.

Total number of electrons possible since each orbital can have maximum of 2 electrons = 10
number of electrons with spin $s=-\frac{1}{2}$ is 5
The other 5 electrons will have the spin $s=+\frac{1}{2}$