Lewis dot structures show the valence electrons of a given atom (both bonded electrons and unbonded electrons). Therefore, each such structure shows the electrons of an atom available for bonding. Generally, atoms prefer to be in a state with eight electrons in the outer shell. These eight electrons are represented by eight places around the chemical symbol of the element. Since atoms prefer to have a filled outer shell, Lewis structures can help predict the bonding behavior of electrons.
Example:
The Lewis structures for two bromine atoms are given.
Each of the bromine atoms in equation (1) is a radical containing an unpaired electron. The Lewis structures predict that the atoms will bond according to the following model.
