Why hydrogen has no neutron?

Hydrogen does not need a neutron for stability in its basic form. A single proton with one electron is already stable, which is why the nucleus of Protium has no neutron.

The most common isotope of hydrogen, called Protium (¹H), has only one proton and no neutron. It’s the simplest and lightest atom. However, other isotopes like Deuterium (²H) and Tritium (³H) do contain neutrons.