Is it true that the size of atoms of inert gases is more than that of halogens?

The given statement is true.

• The outermost shell of inert gases is complete. 
• They have the maximum number of electrons in their outermost orbit thus the electronic repulsions are maximum. 
• The effect of nuclear pull over the valence electrons is not seen. 
• Hence, the size of the atom of inert gas is bigger than that of halogens but not bigger than the alkali metal of the same period.