Draw the Lewis structure (including resonance structures) for the acetate ion (CH3COO- ). For each resonance structure, assign formal charges to all atoms that have formal charge.

Video transcript

Hello everyone. So in this video we're trying to provide resonance structures with the correct formal charges for the oxalate ion, which is C 204 with a two minus formal charge. Alright, so the structure for the oxalate ion is going to be where the central items is carbon, which then one of the carbons will have one double bond oxygen and one single bonded oxygen. Same thing for the other side. Does it matter how it goes? And then to fulfill the double bonded oxygen octet will have two long pairs to fulfill the single bonded oxygen. To fill that octet will have three long pairs. And because we have three long pairs, it's going to be a negative one, formal charge. Let me see this is a negative one from a charge, negative formal charge, the total molecule will have a negative two charge and this is what we want because that's what's stated in the ion. Alright, so like again, this is one of the um structures for the oxalate ion. This can also be one of our resident structures. Then drawing in my readiness structure arrows. Another structure, it's just basically what we're doing is alternating our carbon and oxygen double bond. So maybe instead of this one having the double bond, this one would have the double bond and then this would be the single bond. Said so we can do that first. Again, carbon carbon single bond. So we're saying that this one will be a single bond, this one will be a double bond and this one can have can stay the same having a double bond and a single bond. So right here on the top left, we have a single bond oxygen with three lone pairs giving a negative one from the charge. Then bottom left will have a double bond with two lone pairs, and the right side will stay the same. Alright. Again, with our resident structure arrows. The next thing we can go ahead and alternate is that the left side stays the same, but the right side will flip, meaning that it's hot, right? We'll have a double bond and the bottom right will have a single bond. So again, we have a carbon carbon single bond. The left side stays the same. Okay. And then the right side was going to kind of switch. So on top right, we will have a double bond. And then bottom rights will have a single bond. All right, begin with our resident structure arrows. The last residue structures that we can go ahead and alternates for the carbon oxygen double bond is where basically the top two oxygen's will have double bonds in the bottom two will have single bonds. Let's go ahead and draw that out again. Center is going to be carbon carbon single bond. So we'll have double bond oxygen on the top and the bottom will have single bond oxygen With three lone pairs each giving it a negative one for more church. All right, So these are four resonant structures for our oxalate ion basically we have alternated the carbon oxygen double bond and we have created four different resonance structures. So basically all this here is going to be our final answer for this problem. Thank you all so much for watching.