Polarity is the difference in
energy creating
poles or the lack of any difference created
neutrality.
In polar bonds the electrons are shared unevenly between the two atoms. This causes a difference in charge resulting in two poles, one positive and one negative. Polar molecules are known as dipoles because they have two charged ends.
In nonpolar bonds the electrons are shared evenly between the two atoms making the bond neutral. If a bond contains only nonpolar bonds it will be a nonpolar molecule.
The shape of a molecule and the polarity of its bonds together determine whether a molecule is polar or nonpolar.
The opposite is true for large molecules, the polarity determines the Molecular Shape of a large molecule. A good example of this is protein which can contain thousands of atoms. These molecules have a variety of shapes, such as chains, rings, and balls.