Explanation:
This is due to the reason that in case of inert gases, the outer shell is complete and it has hence maximum electronic repulsion. Moreover in case of inert gases, the atomic size is expressed in terms of Vanderwaal’s radius because, noble gases do not form covalent bonds while other form covalent bonds and hence their atomic radii is expressed in covalent radius. Generally atomic size decreases while moving from left to right in the periodic table. But in the case of noble gases, they have comparatively higher atomic size than corresponding halogens because of the reason that vanderwaal’s radii (present in noble gases) is much larger than ionic and covalent radii (present in other elements). Thus as, Vanderwaal’s radius is greater than covalent radius, the atomic size of noble gases is larger than other elements of same period.
