In Tritium (T), the number of protons (P) and neutrons (N) respectively are

Tritium (H-3) is a radioactive isotope of hydrogen. As an isotope of hydrogen, it possesses an atomic number (Z) of 1, which signifies that it contains exactly one proton in its nucleus [1]. The mass number (A) of tritium is 3, representing the total sum of protons and neutrons. By subtracting the number of protons from the mass number (3 - 1), it is determined that tritium contains two neutrons. This composition distinguishes it from other hydrogen isotopes: protium, which has one proton and zero neutrons, and deuterium, which has one proton and one neutron [1]. Therefore, the nucleus of a tritium atom consists of 1 proton and 2 neutrons [3].

Sources

1. [1] https://www2.lbl.gov/abc/wallchart/chapters/02/3.html
2. [2] https://www.sciencedirect.com/topics/materials-science/tritium
3. [3] https://www.sciencedirect.com/topics/chemistry/tritium-atom