Nature always wants to find the absolute lowest possible energy state for any system. When positive and negative charges move closer together, their overall electrical energy drops significantly. This sudden drop makes the entire atomic system much more chemically stable.
Coulomb’s law gives us the exact mathematical equation for measuring this invisible pulling force. The rule says the attraction grows much stronger if the electrical charges get bigger. For example, an ion with a plus two charge pulls much harder than a plus one charge.
The rule also says the physical distance matters a huge amount in this calculation. If the two charged particles move closer together, the pulling force shoots up very rapidly. If they move farther apart, the attractive pulling force drops off extremely fast.
This specific force holds positively charged protons and negative electrons together inside every normal atom. It also locks opposite ions tightly together to build giant solid crystal shapes. These repeating crystal shapes make up common ionic compounds like regular table salt.
A common student mistake is thinking this force only exists inside ionic bonds. Coulombic attraction is actually hard at work inside every single atom and molecule. It is the fundamental physical reason why any opposite charges ever stick to each other.