Question

Does dipole-dipole bonding only occur between molecules of the same elements?

Answer 1

No, dipole-dipole bonding does not occur between molecules of the same elements. However, dispersion forces do occur between molecules of the same elements.

Explanation:

What are dispersion forces and why do they occur between molecules of the same elements?

• Dispersion forces are the only intermolecular force which occur in molecules of the same element as there is no net dipole as the element has no change in electronegativity. Molecules of the same element are known as non-polar molecules.

• It is caused by momentary dipoles occurring due to uneven electron distributions in neighbouring molecules as they approach one another.

• The weak residual attraction of the nuclei in one molecule for the electrons in a neighbouring molecule.
• The more electrons that are present in the molecule, the stronger the dispersion forces will be.

What are dipole-dipole forces and why don't they occur between molecules of the same elements?

• Dipole-Dipole forces form when there is a large difference in electronegativity between two atoms joined by a covalent bond. The atoms share the electrons unequally.
• In molecules of the same element, there is no change in electronegativity so their can not be any net dipole.
• Thus, dipole-dipole forces occur in polar molecules (molecules with a net dipole).