Molecules having four bond pairs and no lone pair give geometry:

Explanation

The bond pair of electrons in the valence shell repel each other. To minimize the repulsions between the bond pairs, they are arranged at maximum distance from each other. If there are four bond pairs in the valence shell of the central atom, the bond pairs orient itself at an angle of 109.28′ inorder to minimize repulsion. The shape of such a molecule is tetrahedral. For example: In methane molecule the carbon atom (central atom) has four bond pairs (one covalent bond each with four hydrogen atoms). So, the shape of the molecule is tetrahedral shape.