Why do neutral atoms have equal numbers of protons and electrons?

Neutral atoms have equal numbers of protons and electrons because this balance is required to maintain the atom's overall electrical neutrality.12

Within an atom, protons carry a positive electric charge, while electrons carry an equal magnitude of negative charge. Because the charge of a proton is equal and opposite to that of an electron, having an identical count of both particles ensures that the positive and negative charges cancel each other out.132

The number of protons in the nucleus defines the atomic number of an element. In a neutral state, this atomic number also dictates the number of electrons present in the extranuclear region. If an atom gains or loses electrons, the balance is disrupted, and the atom becomes an ion, carrying either a positive or negative net charge.12