Which of the following changes most likely increases the magnitude of the electrostatic attraction between two ions in a crystalline solid, according to Coulomb’s law?
a) Replacing the anion of radius 180pm with an anion of radius 220pm
b) Substituting heavier isotopes of both ions while keeping charge and radius unchanged
c) Replacing a +1 cation with a +2 cation of the same ionic radius
d) Replacing a +2 cation of radius 100pm with a +1 cation of radius 50pm