Question

An element $X$ belongs to $3^{rd}$ period and ${17}^{th}$ group, state

(iii) name the family to which it belongs.

Answer 1

The element that belongs to the $3^{rd}$ period and ${17}^{th}$ group is chlorine $\left(Cl\right)$.
Chlorine belongs to the ${17}^{th}$ group which is also known as halogen family.