**Ammonia NH**_{3} : The electronic configuration of nitrogen is 1s^{2},2s^{2} ,2p_{x}^{1}, 2p_{y}^{2}, 2p_{z}^{1}. If the p_{x}, p_{y} and p_{z} orbitals of N are used to overlap, then the bond angle in NH_{3} should be 90°.

In NH_{3} each N – H bond makes an angle of 107° with the other N – H bonds and its shape is Pyramidal. This fact is explained by the sp^{3} hydridization of N.