Why do oppositely charged particles attract? I know this question was asked on PF a while ago, but the answers given do not seem too convincing. I understand that, by Coulomb's Law, there are attractive and repulsive forces between charged particles, proportional to the product of the particle's charges and inversely proportional to the square of the distance between them. But, for example, why is there an attractive force between electrons and protons? What makes the proton intrinsically different to an electron, what property gives it a different "kind" of charge? I would be grateful if someone could explain to me where the difference in charge stems from.