 So, far we have discussed about resonance and the different conjugated system where the resonance is possible. And we have also discussed about the contributors and we say that we have there are two types of contributors, major contributors and minor contributors. Now we are going to discuss about these contributors only and the stability of these contributors. So, the resonating structures are basically of two types. The first one is equal contributors and the second one is unequal contributors. For example, you see where the resonating structures are equivalent, there are exactly same type of resonating structures. For example, the first one if I write down which is very common and that is the benzene range. So, if you look at these two structures, they look like similar structure. Second one and if I write down the next contributing structure, these are also equal contributing structure. Even the carbonate ion, this also gives you the equal contributing structure if you draw the resonating structure. All equal contributors are, for example, you see if I write down this one CH2 negative C7. Resonance possible? Pi sigma negative charge. So, if you draw the resonating structure of this, it would be CH2 double bond C single bond O minus OH. The same structure we can take here, for example, is this. So, you see in equal contributors what happens? The pi electron is distributed uniformly throughout. So, if you draw the actual structure of this, one negative charge is equally distributed on this and this oxygen atom. So, the charge on this oxygen, when you draw the hybrid structure of this will be minus half and minus half. Here it will be minus 1 by 3, minus 1 by 3 and minus 1 by 3. That is the meaning of equal contributors we have. The pi electrons and lone pairs are equally distributed over the entire molecule, but here it is not same. You see the pi electron is distributed from here to here only. No distribution this side, from here to here only. Here also the pi electron distributes from here to here only. So, in this case the distribution is not uniform and hence these are unequal contributors. One more thing, in case of equal contributors, the stability will be more. The molecule which shows equal contributing structures or equal contributors resonating structure if they gives, it means its stability will be more because the charge distribution is uniform and hence the stability is more. So, all these equal contributors or unequal contributors will have different stability. One of the molecule may be more stable than the other one or less stable than the other one and according to the stability only they will contributes their properties to the resonating hybrid or real hybrid or real structure. So, term I use here resonating hybrid which is nothing but real hybrid, it is real structure, true structure all are same thing. So, what is this resonating hybrid real hybrid real structure? These are the combination of for a given molecule or ion for a given molecule or ion these structures, this structure is the combination of R s. Whatever R s you will draw if you combine all the properties of R s you will get the real structure, the properties of the real structure or real hybrid or if you combine all the structures of resonating structures you will get real hybrid or real structure. So, like I said that on the like these resonating structures have certain stability and according to their stability one of the structure will be major contributors and other ones are minor contributors. Major contributors which are more stable which provides more property to the real structure. So, how do we assign the stability of this resonating structure? That is the next question. How do we assign the stability of these resonating structures? So, for that we have certain set of rules that we have to follow. So, the next point we are going to study over here is the stability of resonating structure.