Homonuclear diatomic molecules

Definition

Homonuclear diatomic molecules are molecules composed of two identical atoms bonded together. Examples include $\text{H}_2$, $\text{O}_2$, and $\text{N}_2$.

5 Must Know Facts For Your Next Test

1. In homonuclear diatomic molecules, electron density is shared equally between the two atoms.
2. These molecules have molecular orbitals that can be bonding or antibonding.
3. The bonding in these molecules can be explained using Molecular Orbital Theory.
4. $\sigma$ and $\pi$ molecular orbitals are formed through the linear combination of atomic orbitals.
5. The bond order in homonuclear diatomic molecules can be calculated using the formula: $(\text{Bond Order} = \frac{1}{2}(\text{number of bonding electrons} - \text{number of antibonding electrons}))$.

Review Questions

• What distinguishes a homonuclear diatomic molecule from other types of molecules?
• How does Molecular Orbital Theory explain the bonding in homonuclear diatomic molecules?
• Calculate the bond order for a molecule with 8 bonding electrons and 4 antibonding electrons.

Related terms

Molecular Orbital Theory: A theory that describes the molecular structure by considering electrons to be delocalized over an entire molecule forming molecular orbitals.

$\sigma$ Bond: A type of covalent bond formed by the head-on overlap of atomic orbitals, resulting in a symmetrical electron distribution along the axis connecting two nuclei.

$\pi$ Bond: A type of covalent bond formed by the side-to-side overlap of atomic orbitals, with electron density above and below the plane of the nuclei.