Which isoelectronic series is correctly arranged in order of increasing radius? A)K⁺

Question

Which isoelectronic series is correctly arranged in order of increasing radius? A)K⁺ < Ca²⁺ < Ar < Cl^- B) < Ar < K⁺ < Ca²⁺ C)Ca²⁺ < Ar < K⁺ < Cl^- D)Ca²⁺ < K⁺ < Ar < Cl^- E)Ca²⁺ < K⁺ < Cl^- < Ar

Quizplus · Accepted Answer

Isoelectronic series have the same number of electrons, hence the radius decreases with increasing nuclear charge. In the given options, Ca²⁺ has the highest nuclear charge due to the presence of calcium (Ca) with a full valence shell. This should have the smallest radius. Next should be K⁺ which has a lower nuclear charge than Ca. After that comes Cl^- with a nuclear charge of -1 due to its extra electron. Finally, Ar should have the largest radius as it has a full valence shell and no extra charge. Hence, the correct order is Ca²⁺ < K⁺ < Cl^- < Ar, which is given in option D.

Which Isoelectronic Series Is Correctly Arranged in Order of Increasing