Thu December 20, 2012 By: Keerthi

resonating structures and hybridisation

Expert Reply
Thu December 20, 2012
Resonance structures are imaginary. They represent extremes of electron location. Resonance can be considered as a valence theory solution to a molecular orbital problem. 
In general chemistry the concept of resonance was introduced through inorganic anions such as NO3-, NO2-, ClO4-, SO4-2, CO3-2


Rule #1: Resonance structures must have the same number of electrons. (you should prove it to yourself by counting them). 

Rule #2: All resonance structures must be valid Lewis dot structures.

Rule #3: The hybridization does not change between resonance structures.

Rule #4: The positions of atoms are the same in all structures.

Rule #5: Resonance structures do not have to be equivalent.

The curved arrow shows “movement” of a pair of electrons. It’s an extremely useful accounting system that lets us keep track of changes in bonding and also in charge. Since electron pairs are present either in bonds or in lone pairs, there are really only four combinations of “moves”. 

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