I apologize for the confusion in my previous response. The statement that an element with an atomic number greater than 82 emits radiation is incorrect. The atomic number alone does not determine whether an element emits radiation or not.
Regarding tritium, it is important to clarify that tritium itself is a radioactive isotope of hydrogen, not an element with an atomic number of 1. Tritium has two neutrons in addition to one proton, giving it a total atomic mass of approximately 3 (hence the name tritium). This makes it different from the more common stable isotope of hydrogen, which is called protium and has only one proton and no neutrons.
Tritium is radioactive and undergoes a process called beta decay, emitting a high-energy beta particle (an electron) in the process. This decay is due to the instability caused by the presence of two additional neutrons in the tritium nucleus, which leads to a conversion of a neutron into a proton, releasing the beta particle.
So, while tritium is not an element itself, it is a radioactive isotope of hydrogen, and its radioactivity arises from the specific arrangement of its nucleons (protons and neutrons) in its nucleus.