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### Tricks for Resonance Structures

Posted: **Fri Nov 02, 2018 12:19 am**

by **LeannaPhan14BDis1D**

Are there any simple tricks to seeing how many resonance structures there could be for a single compound? What about for the resonance structures with formal charge that is not 0, would we have to include all the structures or do we exclude a certain number of formal charge when making resonance structure?

thank you!

### Re: Tricks for Resonance Structures

Posted: **Fri Nov 02, 2018 10:13 am**

by **Chloe Qiao 4C**

I think you need to draw the Lewis structures out to see how many resonance there are for a compound. And for your second question, usually we only choose the best representation(the one with most atoms having formal charge 0 and with the most electronegative atoms having the negative formal charges), and then we change the place of double bonds(if possible) in that representation to draw resonance.

### Re: Tricks for Resonance Structures

Posted: **Sat Nov 03, 2018 11:43 pm**

by **Madeline Motamedi 4I**

My question is, if the formal charge is 0 for all atoms in the bond, is are there resonance structures?

### Re: Tricks for Resonance Structures

Posted: **Sun Nov 04, 2018 2:40 pm**

by **Keshav Bhatnagar 1H**

Madeline Motamedi 3F wrote:My question is, if the formal charge is 0 for all atoms in the bond, is are there resonance structures?

Even though there may be a compound with a formal charge of 0, that doesn't necessarily mean the compound doesn't have any resonance structures. You need to play around with double bonds and delocalizing electrons to find the resonance structures.

### Re: Tricks for Resonance Structures

Posted: **Sun Nov 04, 2018 5:17 pm**

by **JiangJC Dis2K**

Just try to draw as many as possible. Usually it's symettric or the question tells you how many resonance structures to consider. We won't be calculating the actual mixed bond lengths or anything because that's exclusively found experimentally.

### Re: Tricks for Resonance Structures

Posted: **Sun Nov 04, 2018 7:47 pm**

by **almaochoa2D**

I'm pretty sure we won't need to know how many resonance structures we need to draw, the problems will tell us how many resonance we need to draw.