One proton makes a hydrogen atom. The difference between isotopes is the number of neutrons bound to that proton. There are six known hydrogen isotopes, ranging from H-1 to H-6. The H-4 isotope has a range of half-life values, depending on the overall energy of the nucleus and its total angular momentum quantum number. This table lists the hydrogen isotopes, their half-life and type of radioactive decay.
Reference: International Atomic Energy Agency ENSDF database (Oct 2010)
|H-3 (tritium)||12.32 years||β-|
|H-4||5.1 x 10-23 sec - 9.8 x 10-23 sec||n|
|H-6||4.1 x 10-22 sec||n|