91Ó°ÊÓ

Resonance is a method to represent delocalized electrons within certain molecules or polyatomic ions when the bonding cannot be concluded by a single lewis structure.

Resonance occurs when two double bonds are present consecutively, or a double bond is followed by a single bond which is followed by another double bond, triple bond, positive charge, negative charge, or a free radial.

Rule 1

Individual resonance forms are imaginary, which means they are not real. The fundamental structure is a composite or resonance hybrid of all the different states.

Rule 2

Resonance forms differ only in the placement of their or nonbonding electrons. So, the position or the hybridization of any atom doesn’t change.

Rule 3

Different resonance forms of the molecule don’t have to be equivalent. They can be converted into their anion by reaction with a strong base. The resultant anion can have resonance forms.

Rule 4

Resonance forms obey normal rules of valency. Like any other structure, a resonance form has to follow the octet rule.

Rule 5

The resonance hybrid is more stable than any individual resonance form. So, resonance leads to stability. The more the number of resonance structures, the more stability will be.

Structures of resonance possible

We will see if the rules are followed:

Here all rules are followed:

Rule 2: Resonance forms differ only in the placement of their or nonbonding electrons. So, the position or the hybridization of any atom doesn’t change.

Here, the position of only or nonbonding electron is changed.

Rule 4: Resonance forms obey normal rules of valency. A resonance form, like any other structure, has to follow the octet rule.

Here, each atom follows the octet rule.

So, it can be concluded these are two resonating forms possible.