Which of the following has the smallest ionic radius ? cl-1 , s-2 , mg2+ , or ca2+

We know that ionic radii trends have the elements ionic radii increasing right to left in a row and top to bottom in a group with Groups 13-18 having their respective exceptions.

That being said, since Ca2+ and Mg2+ are in the same group, we know that Mg2+ has a smaller radius that Ca2+.

So Mg2+ < Ca2+

And we know that Cl- and S2- are both two large atoms, due to them being found in group 17 and 16 respectively. Both of these atoms have a larger radius than Ca2+ due to them being an exception.

So we can write: Mg2+ < Ca2+ < Cl- and S2-

One way to know the exact figures for sure is to have a table on hand with all of the ionic radii. Using a table, we know that the actual ordering of the atoms is:

Mg2+< Ca2+ < Cl- < S2-

Therefore, Mg2+ has the smallest ionic radius.

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."