Explain Isotopes of Hydrogen with Applications | Isotopes of Hydrogen are tritium, deuterium, and protium

Hydrogen has three naturally occurring isotopes, denoted 1H, 2H, and 3H. Other, highly unstable nuclei (4H to 7H) have been synthesized in the laboratory but are not observed in nature.

1H is the most common hydrogen isotope with an abundance of more than 99.98%. Because the nucleus of this isotope consists of only a single proton, it is given the descriptive, but rarely used the formal name of protium.

2H, the other stable hydrogen isotope, is known as deuterium and contains one proton and one neutron in its nucleus. Essentially all deuterium in the universe is thought to have been produced at the time of the Big Bang, and has endured since that time. Deuterium is not radioactive, and does not represent a significant toxicity hazard. Water enriched in molecules that include deuterium instead of normal hydrogen is called heavy water. Deuterium and its compounds are used as a non-radioactive label in chemical experiments and in solvents for 1H-NMR spectroscopy. Heavy water is used as a neutron moderator and coolant for nuclear reactors. Deuterium is also a potential fuel for commercial nuclear fusion.

3H is known as tritium and contains one proton and two neutrons in its nucleus. It is radioactive, decaying into helium-3 through beta decay with a half-life of 12.32 years. It is sufficiently radioactive that it can be used in luminous paint, making it useful in such things as watches where the glass moderates the amount of radiation getting out. Small amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases; tritium has also been released during nuclear weapons tests. It is used in nuclear fusion reactions, as a tracer in isotope geochemistry, and specialized in self-powered lighting devices. Tritium has been used in chemical and biological labeling experiments as a radiolabel.

Hydrogen is the first element in the periodic table and has atomic number one. Those elements which have the same atomic number but a different mass number are called isotopes. There are three isotopes of hydrogen namely, protium 1H1, deuterium 1H2 or D and lastly tritium 1H3 or T. The isotopes are different because of the different number of neutrons present in them.

In protium, there is no presence of neutrons, whereas in deuterium we have one neutron and in tritium, we have two neutrons. The most prominent form of hydrogen is protium, 0.0156% of hydrogen is present on the earth’s surface as deuterium. In tritium, the concentration is one atom per 1018 atoms of protium. Out of these three isotopes of hydrogen,

Out of these three isotopes of hydrogen, the only tritium is radioactive in nature and emits low-energy b particles. As the electronic configuration of isotopes is the same, they all have similar chemical properties. But they have a difference in their rates of reaction, this happens because of the different bond disassociation enthalpies. They have different physical properties because of the large variations in mass.

The occurrence of hydrogen on earth is difficult due to its light nature. In combination, it forms 15.4% of hydrogen that occurs in the earth’s crust and oceans. Hydrogen also occurs in plant and animal tissues, hydrocarbons, proteins, hydrides, and many other compounds. In the universe, hydrogen is the most abundant element (70% of the total mass) and it is also the principal element of the solar atmosphere. Even the huge planets such as Jupiter and Saturn mainly consist of hydrogen.

Three naturally existing isotopes of hydrogen are tritium, deuterium, and protium.

1. Protium ( 1H )

It is one of the common isotopes of hydrogen. It is plenty in nature with an abundance of 99.98%. One of the reasons for this is that the nucleus of this isotope consists of a single proton and this proton at no time, it has been reported to be decayed. Mass of protium is 1.007825 amu. Hydrogen generally combines with other atoms in compounds and are usually found in H2 ( diatomic hydrogen gas).

2. Deuterium ( 2H)

It comprises 1 proton and 1 neutron in its nucleus. The nucleus of hydrogen 2 is termed as deuteron. It is not radioactive. Its compounds are used in chemical analysis and solvents for hydrogen 1. Heavy water is enriched with molecules consisting of deuterium instead of protium. It used as a coolant and a neutron moderator. Hydrogen 2 is also used as a fuel in nuclear fusion (commercial). It occurs naturally as deuterium gas.

Applications of Deuterium

  • Drugs
  • Nuclear weapons
  • Contrast properties
  • Tracing
  • NMR spectroscopy
  • Nuclear reactors and Nuclear Power Plants

3. Tritium ( 3H )

It comprises 2 neutrons and 1 proton in its nucleus. Small traces of hydrogen 3 or tritium occurs in nature due to the synergy of cosmic rays with atmospheric gases. They are also released in a small amount at the time of nuclear weapons tests. It is radioactive, it decays into helium 3 through beta decay. Hydrogen 3 has an atomic mass of 3.0160492 u.

Applications of Tritium

Analytical chemistry

Controlled nuclear fusion

Tritium in hydrogen bomb secondaries


Neutron initiator

Nuclear weapons

Self-powered lighting

Used as an oceanic transient trace


It comprises 1 proton and 3 neutrons in its nucleus. Hydrogen-4 is a highly unstable isotope of hydrogen. It is incorporated in laboratories bombarding tritium with fast-moving deuterium nuclei. Its atomic mass is 4.02781 ± 0.00011.


It comprises 4 neutrons and 1 proton. Hydrogen-5 is a highly unstable isotope of hydrogen. It has been incorporated in the laboratory by bombarding tritium with fast-moving tritium nuclei.


It has a half-life of 290 yoctoseconds. It decays through triple neutron emission into hydrogen-3.


It comprises 6 neutrons and 1 proton. It has a half-life of 23 yoctoseconds.

How many isotopes are in hydrogen?

The hydrogen element has three isotopes: hydrogen, deuterium, and tritium. We each have a single proton (Z = 1), but the number of their neutrons is different. There is no neutron in hydrogen, one in deuterium, and two neutrons in tritium.

Which isotopes of hydrogen are radioactive?

It has about 12.32 years of half-life. Tritium is hydrogen’s most stable radioisotope. That is, tritium is the least radioactive of all hydrogen radioactive isotopes. Four other radioactive hydrogen isotopes were produced by researchers, but these isotopes are very volatile and simply do not exist.

Is Protium an isotope of hydrogen?

Protium is hydrogen’s most common isotope. It accounts for more than 99.98 percent of all universe hydrogen. Because its nucleus has only one proton, it is called protium. The atomic mass of Protium is 1.00782504(7) u.

Are all isotopes are radioactive?

Those elements with atomic numbers greater than 83 are radioisotopes, which means that they have unstable nuclei and that they are radioactive. They have isotopes (stable nucleus) and most have at least one radioisotope (unstable nucleus).

Are isotopes dangerous?

Radioactive isotopes are types of chemical elements formed by the natural decay of atoms. Radiation exposure is generally considered hazardous to the human body, but in medicine, radioisotopes are highly valuable, particularly in disease diagnosis and treatment.

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