Question

Atoms of 18 group elements have larger atomic size why?

Answer 1

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.

Answer 2

they have more number of shells and number of electrons in outer most shells