The correct order of increasing radius of the elements Si, Al, Na and P is : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Identify that Na, Al, Si, and P all belong to the third period of the periodic table. Step 2: Across a period from left to right, atomic radius decreases because the effective nuclear charge increases while the number of shells remains constant. Step 3: The left-to-right order of these elements is Na (Group 1) > Al (Group 13) > Si (Group 14) > P (Group 15). Consequently, the correct order of increasing radius is P < Si < Al < Na.