Sorry if this is a ridiculously simple problem, but I don't get it. The professor didn't give examples of how to do this and it's been years since I've taken science courses. I have to determine the electric force (Coulomb's Law) on the K+ ion due to the Cl- ion 9E-10m away. How do you determine the charge of the K+ and Cl- ions? K(19) has atomic mass 39.0983 and Cl(17) has atomic mass 35.4527... but I don't know where to start with calculations. Please help? Thank you.