For the symbol H,D and T tabulate three sub-atomic particles found in each of them.

Hydrogen (H) typically has 1 proton and 1 electron in its nucleus, making it the simplest form of hydrogen. Deuterium (D) is an isotope of hydrogen with 1 proton and 1 neutron in its nucleus, alongside 1 electron. Tritium (T), another hydrogen isotope, has 1 proton and 2 neutrons in its nucleus, along with 1 electron.

These variations in the number of neutrons among isotopes result in different atomic masses for each isotope of hydrogen.