Question

Arrange the following in increasing order of their atomic radius : Na, K, Mg, Rb.

• A. Mg < K < Na < Rb
• B. Mg < Na < K < Rb
• C. Mg < Na < Rb < K
• D. Na < K < Rb <. Mg

Answer 1

Answer: (B)

Mg < Na < K < Rb

Atomic radii increases on moving down a group from top to bottom and decreases as we move along a period from left to right. Therefore, the increasing order of atomic radius is Rb > K > Na > Mg.