Concept:Hydrogen possesses three naturally occurring isotopes, differentiated strictly by the number of neutrons in the nucleus.
Solution:- Protium (\(\text{H}^1\)): Contains 1 proton, 0 neutrons. It is highly stable and makes up 99.98% of the universe's hydrogen.
- Deuterium (\(\text{D}^2\)): Contains 1 proton, 1 neutron. It is completely stable and is found in heavy water.
- Tritium (\(\text{T}^3\)): Contains 1 proton and 2 neutrons. Because the neutron-to-proton ratio (2:1) is too high for such a light nucleus, the strong nuclear force cannot maintain stability.
- Consequently, Tritium is unstable and undergoes beta decay with a half-life of 12.3 years.
Why other options are incorrect:Protium and Deuterium are unconditionally stable. Only Tritium is radioactive.
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