Question

How many electrons in an atom have the following quantum numbers?

n = 4, $m_{s}$= - ½

• A. 32
• B. 18
• C. 8
• D. 16

Answer 1

Answer: (D)

16

Answer 2

: n = 4

l = 0, 1,2,3

}{( - 3, - 2, - 1,0, + 1, + 2, + 3)}$$ $$m_{s} = \pm \frac{1}{2}\left( \pm \frac{1}{2}, \pm \frac{1}{2}, \pm \frac{1}{2} \right)\left( \pm \frac{1}{2}, \pm \frac{1}{2}, \pm \frac{1}{2} \pm \frac{1}{2} \pm \frac{1}{2} \right)$$ Total number of electrons with $m_{s} = - \frac{1}{2}$ will be 16.