Dipole

A dipole occurs when areas of a molecule have concentrations of positive charge, whereas other areas have concentrations of negative charge:

  (+ve) H-Cl (-ve)

A molecule with a dipole has become polarised.

There are three types of dipoles:

• Permanent dipoles: These occurs when 2 atoms in a molecule have substantially different electronegativity - one atom attracts electron more than another. See dipole-dipole attractions.

• Instantaneous dipoles: These occur due to chance when electrons happen to be more concentrated in one place than another in a molecule, creating a temporary dipole. See Instantaneous dipole attraction.

• Induced-dipoles These occur when one molecule with a dipole repel another molecule's electrons, causing a dipole. See induced-dipole attraction.