Dear student,
Protium is the most prevalent hydrogen isotope, with an abundance of 99.98%. Protium consists of one proton and one electron.
Protium never present in its mono atomic form but bonded with itself (H2) or other elements. Neutrons is generally required when the proton number in the nucleus is one or more. In this case there is one proton and one electron so the net charge is zero which makes it stable isotope.
Regards