I am doing a challenge problem. Can you tell me if I am correct in my reasoning, and help me out with what I am asking? Thanks! I used Coulomb's law to find the force of attraction between Be2+ and S2- in BeS and between Be2+ and O2- in BeO. Radius(Be) = 59 pm Radius(S) = 170 pm Radius(O) = 140 pm F(BeS) = -6.856x10^29 J/m F(BeO) = -9.078x10^29 J/m 1. I was asked to find the radius of the ion, S. I looked it up to be 170, and it works in Coulomb's equation to get the F, but how do I determine the radius? 2. Is it correct that by this info, that there is a stronger force of attraction between BeO than between BeS? 3. If BeO does have the stronger force of attraction, it should line up with the other ways to determine attraction. The bond length between BeO is smaller than between BeS, which means it has a stronger attraction. Also, O is more electronegative than S, so it will have a stronger ability to attract Be, right? Which is the more important atomic property in determining Coulombic force?