one electron has 0 atomic mass unit
atomic_mass is not mass. hydrogen_atoms has one_proton_and_one_electron hydrogen_atom has not only_one_electron atomic_mass is mass. hydrogen has atomic_number_of_one hydrogen_atoms has not one_proton_and_one_electron hydrogen_atom has only_one_electron equivalent is not atomic_mass. hydrogen has not atomic_number_of_one atomic_mass_unit is not mass_unit.