If positive and negative charges attract each other, why don't electrons just stick to the protons?
Explanation from quantum theory. Esssentially a hydrogen atom ground state is the lowest energy level.
Because electrons and protons are not like small, solid billiard balls. They behave VERY differently than how you're used to objects behaving. There's no simple answer and a proper understanding would require getting into Quantum Theory. If you're interested you can start with the following article: https://en.wikipedia.org/wiki/Introduction_to_quantum_mechanics
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