Look a the animation on the left. Note the impact that the two non-bonding pairs situated on the oxygen atom have on the shape of the molecule.

The four electron clouds around the oxygen take up a tetrahedral arrangement as they repel each other in 3 dimensional space. Click to see an animation. We can also draw molecules using Lewis Dot diagrams..

Balloons can be used to model molecules. Balloons will separate in 3d space to give the appropriate shape, as shown on the right.