Lewis theory is a concept in chemistry that explains how atoms bond together to form molecules. It focuses on the idea that atoms achieve stability by sharing or transferring electrons. This theory introduces the concept of Lewis structures, which are diagrams that represent the arrangement of electrons around atoms in a molecule. In Lewis theory, atoms are depicted as symbols, and dots represent their valence electrons. The sharing of electrons between atoms forms covalent bonds, while the transfer of electrons leads to ionic bonds. This framework helps predict the behavior and properties of various chemical compounds.