Isotopes of Hydrogen: Definition, Properties and Sample Questions

The most abundant element in the universe, hydrogen (H) is a colourless, odourless, flammable gaseous substance and is the simplest member of the family of chemical elements. Hydrogen has three most stable isotopes which are protium (¹H), deuterium (²H) and tritium (³H). Here, we will discuss these three naturally occurring isotopes of hydrogen along with a few important questions.

What are Isotopes of Hydrogen?

The very first element existing in the periodic table is hydrogen with an atomic number of one. There is a ruling that states that those elements that exhibit identical atomic numbers but different mass numbers are considered isotopes.

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Thus there are three isotopes that hydrogen exhibits, namely:

• Protium
• Deuterium
• Tritium

All three isotopes are different, the reason being a varying number of protons.

Protium has no protons while deuterium and tritium have one and two protons respectively. Tritium in all three isotopes is the one that has a radioactive nature and emits beta particles of low energy. All three isotopes have similar chemical properties because of the identical electronic configuration. But they have got a distinction of their rates of reaction, this happens because of the distinct bond dissociation enthalpies. They have specific physical properties because of the big variations in mass.

The occurrence of hydrogen on the planet is difficult because of its mild nature. In combined it forms 15.4% hydrogen takes place within the earth’s crust and oceans. Hydrogen additionally occurs in plant and animal tissues, hydrocarbons, proteins, hydrides, and plenty of different compounds. In the universe, hydrogen is the most abundant element (70% of the total mass) and it is also the primary element of the sun ecosystem. Even the large planets inclusive of Jupiter and Saturn specifically include hydrogen.

A look at each isotope with details:

Protium

Protium is one of the common isotopes of hydrogen. It is lots in nature with an abundance of 99.98%. One of the reasons for this is that the nucleus of this isotope includes a single proton and this proton at no time has been stated to be decayed. Mass of the protium is 1.007825 amu. Hydrogen generally combines with other atoms in compounds and is normally determined in H₂ ( diatomic hydrogen gas).

Deuterium

It accommodates 1 proton and 1 neutron in its nucleus. The nucleus of hydrogen 2 is called a deuteron. It isn't always radioactive. Its compounds are utilized in chemical analysis and solvents for hydrogen 1. Heavy water is enriched with molecules such as deuterium instead of protium and it also works as a coolant and a neutron moderator. Hydrogen 2 is likewise used as gasoline in nuclear fusion (commercial). It takes place evidently as deuterium gasoline.

Tritium

It contains 2 neutrons and 1 proton in its nucleus. Small lines of hydrogen 3 or tritium occur in nature because of the synergy of cosmic rays with atmospheric gases. They also are released in a small amount at the time of nuclear gun checks. It is radioactive, it decays into helium 3 through decay. Hydrogen 3 has an atomic mass of 3.0160492 u.

Heavier Synthetic Isotopes

4H or Hydrogen-4 consists of 1 proton and three neutrons in its nucleus. It is acquired through bombarding Tritium with rapid-transferring deuterium nuclei or deuterons. Its presence was discovered with the aid of detecting the emitted photons. It decays through neutron emission into Hydrogen-3. It is a fantastically volatile isotope of Hydrogen.

5H or Hydrogen-5 is another volatile isotope of hydrogen. Its nucleus includes a single proton and four neutrons. It has been synthesized or obtained via bombarding Tritium with rapid-shifting tritium nuclei. It is capable of decaying via double neutron emission into Hydrogen-3. It has a half-life of 910 yoctoseconds.

6H or Hydrogen-6 decays through triple or quadruple neutron emission into Hydrogen-2. It has a half-life of 290 yoctoseconds. It's incredibly unstable, nearly out of date.

7H or Hydrogen-7 has 1 proton and 6 neutrons. It was obtained with the aid of bombarding hydrogen with helium-8 atoms. It has a half-existence of 23 yoctoseconds.

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Things to Remember based on Isotopes of Hydrogen

• Hydrogen has three naturally occurring isotopes: protium, deuterium and tritium.
• There are other highly unstable nuclei (4H and 7H) that have been synthesized in the laboratory but do not occur in nature. 
• Protium is the most common hydrogen isotope with an abundance of more than 99.98%.
• Deuterium is another stable isotope of hydrogen which has a natural abundance of ~156.25 ppm in the oceans.
• Tritium contains one proton and two neutrons in its nucleus. 
• 4H or Hydrogen-4 consists of 1 proton and three neutrons in its nucleus.
• 5H or Hydrogen-5 is another volatile isotope of hydrogen. Its nucleus includes a single proton and four neutrons.
• 6H or Hydrogen-6 decays through triple or quadruple neutron emission into Hydrogen-2. 

Sample Questions based on Isotopes of Hydrogen

Ques. Are all isotopes radioactive? (2 marks)

Ans. Those elements with atomic numbers of more than 83 are radioisotopes, which means that they've unstable nuclei and that they are radioactive. They have isotopes (stable nucleus) and maximum as a minimum one radioisotope (unstable nucleus).

Ques. Are isotopes dangerous? (2 marks)

Ans. Radioactive isotopes are styles of chemical factors shaped through the earthly decay of atoms. Radiation publicity is typically taken into consideration as hazardous to the human body, however, in medicinal drugs, radioisotopes are rather valuable, especially in disease diagnosis and treatment.

Ques. Which isotope among the three is most unstable? (1 mark)

Ans. Tritium is the most unstable isotope with a half-life of 10 years.

Ques. Are all isotopes of hydrogen flammable? (3 marks)

Ans. Yes, They all have a single electron that luckily paperwork a single bond with oxygen, though their chemical behavior is ever so barely special (mainly, deuterium and tritium undergo all the equal chemical reactions, but extra slowly than protium)

Ques. How many isotopes are there in hydrogen? (3 marks)

Ans. Hydrogen consists of three isotopes: protium, deuterium, and tritium. Where each has a single proton (Z = 1), but the number of their neutrons is different. There is one neutron in protium, two in deuterium, and three neutrons in tritium.

Ques. What are the applications of tritium? (3 marks)

Ans. The applications of tritium are:

• This is used as a radiolabel in biological labelling experiments, 
• Tritium is also used as self-powered lighting devices or radio luminescent light sources 
• used as a radioactive tracer
• Used in beta, voltaic devices in order to create the atomic batter for energy production.

Ques. State the applications of deuterium. (4 marks)

Ans. The applications are as follows:

• ‘Heavy water’ is alternatively used as a neutron moderator 
• Deuterium is used as a coolant for nuclear reactors. 
• Deuterium can work as a prospective fuel for nuclear fusion, amateur fusors, or neutron generators. 
• It is used in prototype fusion reactors as well.

Ques. Which is the most common isotope of hydrogen? (2 marks)

Ans. The most common isotope of hydrogen is protium, whose atomic number is equal to its mass number. It accounts for almost 99% of universal hydrogen.

Ques. Which is the most radioactive isotope of hydrogen? (2 marks)

Ans. The most radioactive isotope of hydrogen is tritium which can be used in radioluminescent light sources.