Consider the following two compounds:
Alright, let's take a look at that question. Now, we have our compound here that I'm going to draw, this is our compound C, where we have this group here and this group right here. Now from here we need to compare this to two other compounds, so this is compound C there are compared to our compound A in our compound B, which one is it going to be more similar to you as far as resonance stabilization goes? Well, what we can do is, let's show our compound A compound a is going to look like this where our group this O is right there, compound B is going to look like this where notice that position of this group changes as well, okay? So, pay attention to these groups. Now, we need to think of resonance, so remember that this oxygen is going to have some lone pairs on it and what we can do is we can make a bond, right? Break a bond then we can make a bond, so we can actually move our charge where one oxygen is going to have a partial or a positive, right? one's going to have a negative and where we can do the same thing for our other compounds where here we can make bond, break bond, make bond, break bond. So, again we're going to have a negative there and a positive here, but A, notice that the position is different. Notice that it's, if this is one it's at position three over here, where before it was at position 2 and at position four, right? Where we can we have 1, 2 and 1, 2, 3, 4. Notice that the position is different for this one, so we actually show the resonance capabilities of it, you can make a bond, break a bond but we have to go in this direction where the other compounds can go around the ring as well but compound A will only get a charge on one oxygen atom or compound C and compound B will get charges on both oxygen atoms, so what do you think is compound C going to be more similar to compound B or compound A? Well, compound B is going to have a greater resonance stabilization than A. So, compound C is going to be very similar to B where since it can push its electrons to one oxygen and the other giving them both partial charges or one positive and one negative charge, we should expect compound C to be more similar to compound B and have a greater resonance stabilization than compound A. Alright guys, hopefully that makes sense.