CHEMISTRY COMMUNITY

Question 5B. on the 2014 Midterm: Arrange S^2-, Cl-, and P^3- in order of increasing ionic radius.

It was not CL>S>P

They are all isoelectronic, so basically the one with a lower effective nuclear charge would have a higher ionic radius (essentially, the one with less protons). Thus, in increasing ionic radius form, that would be Cl^-<S^2-<P^3-.

Nice answer, Ronald.