MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

In a given period, the atomic radius decreases from left to right as the effective nuclear charge increases. This trend continues up to group 17 (halogens). For group 18 (noble gases), the atomic radius is expressed as van der Waals radius since they do not form covalent bonds under normal conditions. Since van der Waals radii are always larger than covalent radii, group 18 elements have larger radii than group 17 elements. Thus, group 17 elements possess the smallest atomic radii in their respective periods. Answer: group 17