Question

which of the following has the largest atomic radius? n p s se

Explanation:

Atomic radius increases down a group and decreases across a period. N (Nitrogen) is in period 2, P (Phosphorus) and S (Sulfur) are in period 3, and Se (Selenium) is in period 4. Among these, Se has the highest period number. Also, within the same period, atomic radius decreases from left to right (P > S). But since Se is in a lower period (higher period number means more electron shells, larger radius), it has the largest atomic radius.

Answer:

Se