That Do Not Conform to the Octet Rule

By now, a number of examples of bonding have been shown that are explained very well by the octet rule. There are numerous exceptions to the octet rule, however. These fall into the three following major categories  

Molecules with an uneven number of valence electrons. A typical example is nitric oxide, NO. Recall that the nitrogen atom has 5 valence electrons and the oxygen atom 6, so that NO must have 11, an uneven number. The Lewis structure of NO may be represented as one of the two following forms (these are resonance structures, which are discussed later in this section)  

Nitix en atom has only 7 outer shell electrons. 

Molecules in which an atom capable of forming an octet has fewer than 8 outer electrons. A typical example is highly reactive, toxic, boron trichloride, BCI3  

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