Trick to identify Resonance in a molecule or Ion | How to draw resonance structures – Organic Chemistry

Do you Know !!!

What is resonance?

Resonance is the way of describing delocalized electrons with in a certain molecule or polyatomic ion Where the bonding can not be expressed by  a single Lewis structure.

Molecule / Ion (with delocalized electrons) are represented by several Lewis structures, known as Resonance Structures(Imaginary Structures).Double headed arrow between several structures represents resonance structures (also known as contributing structures ).

More the resonance structures = More stable the molecule or ion

Real structure is average of several resonating structures ,known as Hybrid Structure.

Molecules or polyatomic ions having delocalized electrons are loosely attached and can move freely with in a molecule due to conjugation.

Trick to find resonance !!!

The simplest trick to find resonance is to check conjugation in a molecule / ion.

If the molecule /ion having conjugation then due to this delocalization of electrons occur in it ,results in resonance .

Let’s look at the different types of conjugation in a diagram :

Example of Resonance:

Here you can see the two resonance structure formed due to the delocalization of electrons(conjugation), where the sigma electrons and atoms are at fixed position ,only pi electrons and positive charge change their position.

Hybrid structure is a real structure which is the average of these two resonance structures .Here pi electrons are represented by doted line indicated the partial presence of pi electrons at both positions due to delocalization .Also partial positive charge indicates the presence of partial + charge on both carbon atoms.

In simple words, resonance increase the stability of a molecule or polyatomic ion due to delocalization of electrons.

Watch Now !!

How to draw Resonance structures Tricks ( in Urdu / Hindi) | Class 11 Organic Chemistry

Also Read !!

Inductive Effect

Hyperconjugation | Hyperconjugation Effect in Carbocation 

What is Carbocation?

Carbocation and its Classification

Methyl Radical

Difference between Carbocation and Carbanion

Free Radical

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4 thoughts on “Trick to identify Resonance in a molecule or Ion | How to draw resonance structures – Organic Chemistry”

  1. An outstanding share! I have just forwarded this onto a co-worker who was conducting a little research on this. And he actually ordered me dinner due to the fact that I found it for him… lol. So allow me to reword this…. Thanks for the meal!! But yeah, thanks for spending time to discuss this subject here on your blog.

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