Question

Arrange these atoms and ions in order of decreasing radius:

K+ Ar Cl-

Answer 1

Cl- > Ar > K+

Step-by-step explanation:

Due to the fact that they have different nuclear charges, it means their radius will be different.

Now, the positive charge (cation) with the greater charge value will possess a smaller radius due to the fact that its electrons will have greater attraction to its nucleus.

So, the lesser the value of the charge, the larger the radius.

In the question, K+ has the highest value of charge and thus the smallest radius while Cl- has the lowest value of charge and thus the largest radius. So the correct order in decreasing size is;

Cl- > Ar > K+