State the electronic configurations of Group-$17$ elements.

(N/A) The general valence shell electronic configuration of Group-$17$ elements (halogens) is $ns^{2} np^{5}$. The specific electronic configurations for each element are given below:

Element	Electronic Configuration
${}_{9}F$	$[He] 2s^{2} 2p^{5}$
${}_{17}Cl$	$[Ne] 3s^{2} 3p^{5}$
${}_{35}Br$	$[Ar] 3d^{10} 4s^{2} 4p^{5}$
${}_{53}I$	$[Kr] 4d^{10} 5s^{2} 5p^{5}$
${}_{85}At$	$[Xe] 4f^{14} 5d^{10} 6s^{2} 6p^{5}$
${}_{117}Ts$	$[Rn] 5f^{14} 6d^{10} 7s^{2} 7p^{5}$

These elements have seven electrons in their valence shell. Halogens are highly reactive because they have a strong tendency to gain one electron to achieve a stable noble gas configuration.