Why do noble gases have comparatively large atomic sizes?
There are different kinds of bonds formed by the element when it forms compounds with itself. Depending upon the type of this bond, atomic radius is categorized as follows: (1) Covalent radius: when the element forms a covalent bond with itself, they are in contact with each other and the atomic radius of each atom is equal to the half of their internuclear distance. (2) Vander-waal radius: when there is no bond between the elements but vander waals forces are there when these elements are at the shortest possible distance. In this case also, the atomic radius is half of the internuclear distance. As per the above explanation, it can be inferred that : vander-waal radius > covalent radius Now, it is a known fact that noble gases have completely filled orbitals in terms of electronic configuration. Hence, they do not form covalent bonds usually. Only vander waals forces are there. Hence, the atomic radius of noble gases is larger.
