Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

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Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

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Salim Ahmed Kawsar · Answer 1 · Feb 05, 2023 15:29:48

The ionization enthalpy of hydrogen atom is very high (1312 kJ mol^–1 ). Hence, it is very hard to remove its only electron. As a result, its tendency to exist in the monoatomic form is rather low. Instead, hydrogen forms a covalent bond with another hydrogen atom and exists as a diatomic (H₂) molecule.

Salim Ahmed Kawsar · Answer 2 · Feb 05, 2023 15:29:48

Hydrogen has an electronic configuration of \(1{s}^{1}\). Its outer shell is not complete. So, hydrogen forms covalent bond with another hydrogen atom which results in completely filled shell of electrons which is much more stable than half filled shell. Hence, hydrogen occurs in a diatomic form rather than in a monoatomic form under normal conditions.

Salim Ahmed Kawsar · Answer 3 · Feb 05, 2023 15:29:48

Hydrogen atom has only one electron and thus, to achieve stable inert gas configuration of helium, it shares its single electron with electron of another hydrogen atom to form a stable diatomic molecule. The stability of H₂ is further confirmed by the fact, that formation of one mole of gaseous H₂ molecules results in the release of 435.8 kJ of energy.

H(g) + H(g) H₂ (g); ∆H = – 435.8 kJ mol^-1

Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

3 Answers