Tritium is highly radioactive among all the isotopes of hydrogen. It is denoted by the symbol "T" or "3H" and has two neutrons in its nucleus. Tritium is an unstable isotope and undergoes radioactive decay, emitting a low-energy beta particle (an electron) in the process.

Below are the reasons why tritium is highly radioactive:

1. Unstable Nature:
- Tritium is an unstable isotope because it contains one proton and two neutrons in its nucleus, making it heavier than the stable isotopes of hydrogen - protium and deuterium.
- The extra neutron in tritium makes the nucleus less stable, causing it to undergo radioactive decay.
- This instability leads to the emission of radiation in the form of a beta particle to achieve a more stable configuration.

2. Radioactive Decay:
- Tritium undergoes beta decay, which is a type of radioactive decay.
- During beta decay, one of the neutrons in the tritium nucleus is converted into a proton, and an electron (beta particle) is emitted.
- The decay equation for tritium is:
3H → 3He + e- + νe
(Tritium decays into helium-3, emitting an electron and an electron antineutrino.)

3. Half-life:
- Tritium has a relatively short half-life of about 12.3 years.
- The half-life of an isotope is the time it takes for half of the radioactive nuclei to decay.
- Due to its short half-life, tritium decays at a faster rate than other radioactive isotopes, making it highly radioactive.

4. Health Risks:
- Tritium radiation is hazardous to living organisms, particularly when it enters the body through ingestion, inhalation, or absorption.
- Beta particles emitted by tritium can penetrate the skin and cause damage to internal organs.
- Tritium can also easily combine with oxygen to form tritiated water, which can enter the body through drinking contaminated water.

In conclusion, tritium is highly radioactive because of its unstable nature, beta decay, short half-life, and associated health risks. It is important to handle tritium and its sources with caution due to its potential harmful effects.

Its Tritium....