This type of clothing should not be worn for parties, weddings and other formal or ceremonial events. They should not also be worn for work. Various items of clothing such as tee-shirts, denims, khakis, jackets, hoodies, mini-skirts, summer dresses, loafers, sneakers, and sandals are casual wear.
The presence of a lone pair decreases the bond angle between the bonding pair of electrons, due to their high electric charge which causes great repulsion between the electrons. They are also used in the formation of a dative bond.
For example, if you have 4 pairs of electrons but only 3 bonds, there must be 1 lone pair as well as the 3 bonding pairs. Finally, you have to use this information to work out the shape: Arrange these electron pairs in space to minimise repulsions. How this is done will become clear in the examples which follow.