How do the ionic radii of #Fe^(2+)# and #Fe^(3+)# compare?

1 Answer
Feb 13, 2017

What do you think? I am hardly sticking my neck out if I predict that the ionic radii of the #"ferric ion"# IS MARKEDLY LESS than that of the #"ferrous ion"#. Why?


You know (i) that the atom is mostly empty space; and (ii) that atomic radius can be estimated on the basis of the valence electrons. In the case of #"ferric ion"# you have removed 3 of these valence electrons, and the ionic radius should decrease appropriately. And now this is your job: find estimates for atomic and ionic radius on the web, and see how they compare.