Among the elements Ca , Mg , P and Cl , the order of increasing atomic radii is

Step-by-step solution

With increase in the number of electrons in the same shell, the atomic radii decreases due to increase in effective nuclear charge. However, atomic radii increases, as the number of shells increases. Thus, on moving down a group atomic radii increases. The electronic configuration of the given elements is aligned Mg ₁₂ & =[ Ne ] 3 ~s ^2 Ca ₂₀ & =[ Ar ] 4 ~s ^2 aligned array r P ₁₅=[ Ne ] 3 ~s ^2 3 p ^3 Cl ₁₇=[ Ne ] 3 ~s ^2 3 p ^5 array In Mg , P and Cl , the number of electrons are increasing in the same shell, thu