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Occurrence and Isotopes of Hydrogen

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With an atomic number of 1, hydrogen is the first element in the periodic table. It is the lightest known element. In 1766, Henry Cavendish discovered it. He made the gas by dissolving iron in dilute HSO. Lavoisier proposed the term hydrogen because it produces water when burned with oxygen (‘hydro’ means water and ‘gene’ means producing). Hydrogen is important in industry because it can be used to make a wide range of chemicals. The occurrence of hydrogen and its isotopes are described further below.

Occurrence of hydrogen

The most abundant element in the universe is hydrogen, as well as on Earth. Hydrogen atoms make up nearly nine out of every ten atoms in the universe. Hydrogen can be found in the free state of some volcanic gases as well as the outer atmospheres of the sun and other stars in the universe. According to astronomers, hydrogen atoms make up 90% of the universe’s atoms. 

Hydrogen contributes to around half of the mass of the sun and several other stars. Jupiter and Saturn are predominantly hydrogen-based planets. The sun and stars’ exceptionally high temperatures enable the nuclear fusion of hydrogen atoms, which releases a tremendous amount of energy.

After oxygen and silicon, it is the third most abundant element on the planet’s surface. Hydrogen is perhaps the simplest of all the elements. Its atoms are typically made up of one proton and one electron. The element hydrogen is found in more compounds than any other. Water is the most prevalent hydrogen compound on the earth. 

Hydrogen is found on Earth in a variety of forms, mostly in combination with oxygen in the form of water, and in combination with carbon, nitrogen, and halogens in the form of organic matter in plant and animal tissues, carbohydrates, proteins, and other substances. Hydrogen is found in a variety of minerals, including coal, petroleum, oil, and natural gas. It makes up 15.4% of the earth’s crust and seas. It’s not found in our atmosphere because the earth’s gravitational pull isn’t strong enough to hold light hydrogen molecules. It is tenth in the order of abundance in crystal rocks. Hydrogen atoms make up about 15% of all the atoms on the earth.

Isotopes of Hydrogen

Isotopes are distinct forms of the same element with different mass numbers but the same atomic number. Hydrogen has three isotopes, each with a mass number of 1, 2, or 3. Protium, deuterium, and tritium are the three naturally occurring hydrogen isotopes. 

Due to the various numbers of neutrons in each isotope, the isotopes differ. In nature, the relative abundances of three isotopes are 1: 1.56×10-2: 1×10-18, respectively. Protium atoms make up the majority of hydrogen found in nature. There are no neutrons in protium, while one neutron is present in deuterium and two neutrons are present in tritium. Protium is the most common form of hydrogen, with deuterium accounting for 0.0156% of all hydrogen on the planet’s surface.

Only tritium, out of these three hydrogen isotopes, is radioactive in nature and generates low-energy β-particles. Isotopes have similar chemical properties because their electrical arrangement is the same. However, because of the varied bond disassociation enthalpies, they have distinct reaction rates. Due to the enormous differences in mass, they have different physical properties. 

The outer shell of all three hydrogen isotopes has one electron while the nucleus has only one proton. They do, however, differ in terms of the number of neutrons. Their chemical properties should be similar because the isotopes have the same atomic number and electronic configuration.

Protium (1H1)

The basic hydrogen atom, protium, has a single proton surrounded by a single electron. An element’s isotope is described as an atom with the same number of protons but a different number of neutrons. The letter H is used to denote protium, which is the normal form of hydrogen. Protium is made up of one proton and no neutrons. In contrast to the common hydrogen atom, which has one proton, one electron, and zero neutrons, deuterium possesses one neutron and one proton.

It is one of the most common hydrogen isotopes. It is abundant in nature, with a 99.98 % abundance rate. One of the reasons for this is that the nucleus of this isotope is made up of only one proton, which has never been recorded to decay. Protium has a mass of 1.007825 amu. H2 is a common example of hydrogen combining with other atoms in compounds ( diatomic hydrogen gas). Since this isotope’s nucleus is made up of only one proton, it is given the descriptive, but rarely used term protium.

Uses of Protium

  • Pantoprazole, which is provided as an active ingredient in Protium, is available.
  • It can be used to treat ailments caused by stomach and intestine acid.
  • Protium is also a selective “proton pump inhibitor” a medication that lowers the quantity of stomach acid produced.

Deuterium (1H2)

Heavy hydrogen, often known as deuterium, is one of the stable isotopes of hydrogen. Deuterium gets its name from the Greek word deuterons, which means “second.” A deuteron is a name for the nucleus of a hydrogen-deuterium atom, which contains one proton and one neutron. In the oceans, deuterium is found in a natural abundance of around one atom for every 6420 hydrogens. As a result, deuterium accounts for about 0.025% (0.03% by mass) of all hydrogens found naturally in the seas, whereas protium provides for the remaining 99.98%.

One proton and one neutron make up its nucleus. The deuteron is the nucleus of hydrogen 2. It is not a radioactive substance. Its compounds are utilized as hydrogen 1 solvents and in chemical analysis. Heavy water is enriched with deuterium-based molecules rather than protium-based molecules. It’s utilized as a neutron moderator and a coolant. Nuclear fusion also uses hydrogen 2 as a fuel. It is found in nature as deuterium gas.

Deuterium, the other stable hydrogen isotope, has a nucleus that contains one proton and one neutron. All of the deuteriums in the universe are assumed to have been created at the Big Bang and have survived since then. Deuterium is not radioactive and poses no major risk of toxicity. Heavy water is water that contains deuterium instead of regular hydrogen in its molecules. Heavy water is utilized in nuclear reactors as a neutron moderator and coolant. Deuterium could possibly be used as a commercial nuclear fusion fuel.

Uses of Deuterium

The following are the uses of the deuterium atom.

  • In heavy water moderated fission reactors, they are utilized as a tracer in nuclear fusion reactors to slow down the neutrons.
  • In prototype fusion reactors, the deuterium atom is typically utilized. Deuterium atoms are also used in military, industrial, and scientific applications.
  • In chemical investigations and in solvents for 1H-NMR spectroscopy, deuterium and its derivatives are utilized as non-radioactive labels.

Tritium (1H3

Due to the instability and radioactivity of its nucleus, tritium is the rarest isotope of hydrogen. Two neutrons and one proton make up its nucleus. Due to the interaction of cosmic rays with atmospheric gases, small amounts of hydrogen 3 or tritium can be found in nature. They’re also released in small amounts after nuclear test explosions. It is radioactive, and beta decay transforms it to helium 3. Also, 3.0160492 u is the atomic mass of hydrogen 3.

It is sufficiently radioactive to be utilized as luminous paint, making it helpful in clocks where the glass moderates the quantity of radiation that escapes. Small amounts of tritium are produced naturally when cosmic rays interact with atmospheric gases. Tritium has also been generated during nuclear weapons tests. It’s utilized in nuclear fusion reactions, as an isotope geochemistry tracer, and in self-powered illumination devices. Tritium has been utilized as a radiolabel in chemical and biological labelling research.

Uses of Tritium

The following are the uses of the tritium atom.

  • In biology, tritium is widely used to indicate hydrogen, and hence in metabolic studies. As a result, we were able to lower the biological half-life inside the human body to between 6 and 9 days.
  • Tritium has replaced radium in the manufacture of luminous dials for watches and navigational devices in ordinary life.
  • The high levels of atmospheric nuclear weapons testing that happened prior to the adoption of the Partial Test Ban Treaty were unexpectedly beneficial, according to oceanographers. The enormous amounts of tritium oxide discharged into the ocean’s upper layers have been utilized to determine the rate of mixing between the upper and lower levels.
  • Tritium can be found in the radioactive waste produced by reprocessing facilities and military bases because it can be manufactured in reactor core nuclear fuel through ternary fission processes, which are quite rare.

Sample Question

Question 1: Which is the most common hydrogen isotope?


Protium is the most prevalent isotope of hydrogen. It contains more than 99.98 percent of all hydrogen in the universe. It’s termed protium because its nucleus only has one proton.

Question 2: Which hydrogen isotopes are radioactive?


Tritium is the most stable radioisotope of hydrogen. Tritium, in other words, is the least radioactive of all the hydrogen isotopes. Researchers created four more radioactive hydrogen isotopes, however, they are extremely volatile and simply do not exist.

Question 3: How many isotopes does hydrogen contain?


Hydrogen has three isotopes, that are protium, deuterium, and tritium. Each of us has a single proton, but the number of neutrons differs. In hydrogen, there is no neutron; in deuterium, there is one neutron; and in tritium, there are two neutrons.

Question 4: Is it accurate that isotopes are dangerous?


Radioactive isotopes are chemical elements created by atoms decaying naturally. Radiation is often thought to be harmful to the human body, however, radioisotopes are extremely useful in medicine, notably for illness detection and therapy.

Question 5: Is tritium a dangerous substance?


Tritium has no chemically hazardous properties, and its ability to emit ionizing radiation (the beta particle) is the only risk to human health. As a result of this radiation exposure, the risk of having cancer during one’s lifetime may be somewhat enhanced.

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Last Updated : 29 Nov, 2021
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