The composition of tritium is
A. 1 electron, 1 proton, 1 neutron
B. 1 electron, 2 protons, 1 neutron
C. 1 electron, 1 proton, 2 neutrons
D. 1 electron, 1 proton, 3 neutrons

Hint: Tritium is a rare and radioactive isotope of hydrogen. It is also known as hydrogen-3. Hydrogen is a chemical element symbol H having atomic number 1. It carries one proton, one electron, and no neutrons.

Complete Step by Step Answer:
Hydrogen possesses three isotopes: protium, \[_1^1H\] deuterium, \[_1^2H\] or D and tritium, \[_1^3H\] or T.
Tritium or hydrogen-3 is an uncommon and radioactive isotope of hydrogen.
The nucleus of tritium comprises one proton and two neutrons.
The nucleus of the typical isotope hydrogen-1 (protium) comprises one proton.
Hydrogen-2 (deuterium) comprises one proton and one neutron. It is also called heavy hydrogen.
The dominant form is protium.
Terrestrial hydrogen has some percentage of deuterium. The tritium concentration is about one atom per 1018 atoms of protium.
Only the isotope tritium is radioactive and emits low-energy\[\beta \]–particles.
So, the composition of tritium is 1 electron, 1 proton, and 2 neutrons.
So, option C is correct.

Additional Information: Tritium is utilised as the power source in radio luminescent lights for watches, gun sights, multiple devices and tools, like self-brightening key chains. It is used as a radioactive tracer. Tritium and deuterium are utilised as nuclear fusion fuels.

Note: It must be noted that the isotopes have identical electron configurations, so they have nearly identical chemical properties. The only dissimilarity is in their speeds of reactions, mainly due to their specific enthalpy of bond dissociation. But due to their large mass difference, they have different physical properties.