1. The problem statement, all variables and given/known data Calculate the force of attraction between Ca2+ and O2- ions whose centers are separated by 1.25 nm. 3. The attempt at a solution Well, I belive this is a matter of electrostatic force (Coulomb's Law)...but I am not sure what to use for the values of q1 and q2 Is it just the elementary charge multiplied by 2 for each ion (since they both have a net charge of 2)? Is this the right idea?