Number of valence electrons in \(Cl^- \) ion are:

(a) 16

(b) 8

(c) 17

(d) 18

(b) 8

EXPLANATION

The atomic number of chlorine is 17.

So the electrons are distributed in different shells as follows:-

K-shell has 2 electrons;
L-shell has 8 electrons;
M-shell has 7 electrons;

Chlorine atom has 7 electrons in its outermost shell but \(Cl^-\) has one extra electron and this electron comes in the last shell which is the M-shell, thus the last shell electrons or the valence electrons of \(Cl^-\) is 8.