The correct order of increasing atomic radius of the following elements is : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Note the positions of the elements: O and Se are in Group 16 (Periods 2 and 4), C is in Group 14 (Period 2), and S is in Group 16 (Period 3). Step 2: Atomic radius increases down a group (O < S < Se) and decreases across a period from left to right (so O < C). Second-period elements (O and C) are significantly smaller than third-period (S) and fourth-period (Se) elements. Step 3: Combining these trends, the correct increasing order of atomic radius is O < C < S < Se.