Question

The total spin and magnetic moment for the atom with atomic number 7 are :

• A. $\pm$3, $\sqrt{3}$ BM
• B. $\pm$1, $\sqrt{8}$ BM
• C. $\pm$$\frac{3}{2}$, $\sqrt{15}$ BM
• D. 0, $\sqrt{8}$ BM

Answer 1

The correct option is C $\pm$$\frac{3}{2}$, $\sqrt{15}$ BM

The electronic configuration are:

$N_7$ = $1s^2,2s^{2}2p^3;$ unpaired electron = 3 ;

$\therefore$ Total spin for an atom = $\frac{1}{2}\times$ No. of unpaired electron

For $N_7,$ it is $\frac{\pm 1}{2}\times 3=\pm \frac{3}{2}$

Also magnetic moment = $\sqrt{n(n+2)}$

For $N_7$ it is $\sqrt{3(3+2)}=\sqrt{15}$ B.M

Hence, option C is correct .