Dipole: A dipole is said to exist when two charges of equal magnitude but opposite signs are separated by a small distance.

The overall dipole in a molecule depends on:

The electronegativity of the elements in the molecule
- If there is a large electronegativity difference between the elements in the molecule, this will increase the magnitude of the dipole
The relative angles of the bonds
- If the molecule is symmetrical in all directions, the individual dipoles will cancel each other out and the molecule will be non-polar.
- If the molecule is not symmetrical in all directions, then the dipoles will reinforce each other, the molecule will possess an overall dipole and is said to be polar.

Shapes of Molecules and Ions