Why is Hydrogen Diatomic? (+ 3 Fascinating Facts to Know)

Hydrogen is diatomic because it has a single electron in its valence shell. 1 In order to achieve a stable electron configuration, hydrogen atoms share their electrons with each other to form a diatomic molecule (H2). The covalent bond between the two hydrogen atoms is very strong, which is why hydrogen (H2) is such a stable molecule. 2

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Key Takeaways: Why is Hydrogen Diatomic?

  • Hydrogen is a diatomic molecule because it has a single electron in its outermost shell, which makes it very reactive and prone to bond with other atoms. 
  • Two hydrogen atoms bond together by sharing their electrons to form a stable and strong covalent bond, creating a more stable configuration than they would have individually. 
  • Hydrogen atoms bond to form a diatomic molecule through a covalent bond by sharing electrons to create a stable molecule with a full valence shell for each atom. 
  • The covalent bond in a hydrogen molecule is very strong and requires a lot of energy to break.

Explanation: Why is hydrogen a diatomic molecule?

Hydrogen is a diatomic molecule because it has a single electron in its outermost shell. This means that it is very reactive and wants to form a bond with another atom in order to achieve a full outer shell. 3

When two hydrogen atoms bond together, they share their electrons and form a covalent bond. 4

This bond is very strong and stable, which is why hydrogen is a diatomic molecule.

In simple words, hydrogen is a diatomic molecule because it is more stable as a molecule than as an individual atom. 

When two hydrogen atoms combine, they form a covalent bond, which is a strong and stable bond. 

This bond allows the hydrogen atoms to share electrons and achieve a full outer shell, which makes them more stable.

Does monatomic hydrogen exist?

Yes, monatomic hydrogen exists. 5 It is a gas that is composed of individual hydrogen atoms, rather than molecules. Monatomic hydrogen is very rare in nature, but it can be created in the laboratory. It is also found in the sun and other stars.

Monatomic hydrogen is more stable than diatomic hydrogen at very low temperatures. 6 This is because the atoms in monatomic hydrogen are not bonded together, so they do not have to share electrons. As a result, they have less energy and are therefore more stable.

Monatomic hydrogen has a number of potential applications. It can be used as a coolant in nuclear reactors, and it can also be used as a fuel for spacecraft. 7 8 9 It is also being studied as a possible alternative to helium as a lifting gas for balloons and airships. 10

How do hydrogen atoms bond to form a diatomic molecule?

As I mentioned earlier, hydrogen atoms bond to form a diatomic molecule through a covalent bond. A covalent bond is a type of chemical bond that involves the sharing of electrons between two atoms. 

In the case of hydrogen, each atom has one electron in its valence shell. When two hydrogen atoms come together, they can share their electrons to form a covalent bond. This bond creates a stable molecule with a full valence shell for each atom.

The following steps describe how hydrogen atoms bond to form a diatomic molecule:

  • Two hydrogen atoms approach each other.
  • The positive nucleus of each atom attracts the negative electrons of the other atom.
  • The electrons of the two atoms begin to share space around both nuclei.
  • The atoms are now bonded together by a covalent bond.

The distance between the two hydrogen atoms in a diatomic molecule is about 74 pm. 11 This is the distance at which the attractive force between the nuclei and the electrons is balanced by the repulsive force between the nuclei.

The covalent bond in a hydrogen molecule is very strong. It takes a lot of energy to break this bond. This is why hydrogen is so unreactive. 12

It is very difficult to remove an electron from a hydrogen atom, and it is even more difficult to break the covalent bond between two hydrogen atoms.

Further reading

Is Hydrogen a Compound?
Why is Hydrogen Flammable?
Does Hydrogen have Neutrons?
Is Helium Flammable?
Why Is Helium a Noble Gas? 

About author

Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. He is a founder of Pediabay and is passionate about helping students through his easily digestible explanations.

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  1. Hydrogen – Element information, properties and uses | Periodic Table. (n.d.). Hydrogen – Element Information, Properties and Uses | Periodic Table. https://www.rsc.org/periodic-table/element/1/hydrogen
  2. 9.4: Energy and Covalent Bond Formation. (2016, June 27). Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/09%3A_Covalent_Bonding/9.04%3A_Energy_and_Covalent_Bond_Formation
  3. The Chemistry of Hydrogen. (n.d.). The Chemistry of Hydrogen. https://chemed.chem.purdue.edu/genchem/topicreview/bp/ch10/hydrogen.php
  4. Hawaii.edu https://www.manoa.hawaii.edu/exploringourfluidearth/chemical/chemistry-and-seawater/covalent-compounds
  5. Europhysicsnews https://www.europhysicsnews.org/articles/epn/pdf/1980/05/epn19801105p9.pdf
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  9. Garay, P. N. (1960, July 1). HYDROGEN AS A REACTOR COOLANT (Journal Article) | OSTI.GOV. HYDROGEN AS a REACTOR COOLANT (Journal Article) | OSTI.GOV. https://www.osti.gov/biblio/4143730
  10. Bring back hydrogen lifting gas – The CGO. (2021, August 9). The CGO. https://www.thecgo.org/benchmark/bring-back-hydrogen-lifting-gas/
  11. 4.4: Characteristics of Covalent Bonds. (2017, June 1). Chemistry LibreTexts. https://chem.libretexts.org/Courses/University_of_South_Carolina__Upstate/USC_Upstate%3A_CHEM_U109_-_Chemistry_of_Living_Things_(Mueller)/04%3A_Covalent_Bonding_and_Simple_Molecular_Compounds/4.4%3A_Characteristics_of_Covalent_Bonds
  12. Perrin, C. L., & Nielson, J. B. (1997, October). “STRONG” HYDROGEN BONDS IN CHEMISTRY AND BIOLOGY. Annual Review of Physical Chemistry, 48(1), 511–544. https://doi.org/10.1146/annurev.physchem.48.1.511

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