Protons are positively charged. Like charges repel, so protons fly apart unless there’s an equal number of electrons (or other negatively charged particles) to keep them happy.

Electrons are negatively charged, and fly apart unless there’s a more-or-less equal number of protons. Electrons are a lot lighter than protons so move easier, and electrons deciding to be somewhere with more protons and less electrons is basically lightning.

Neutrons don’t have an electrical charge. They just sit there being gravitational.