sapling week5/6 hw Q4

[Christine Nguyen 3D]

Hi I was wondering if anyone could help me in identifying a second resonance structure for the carbamate ion, I already got the first one where I changed the bond between N and C into a double covalent bond. I'm not sure what else I can modify to get the same number of electrons and formal charges.

If anyone has some pointers or have already done this problem, any help is appreciated!! Thanks :)

[Jenny Chau 1I]

Hi! You could change bond between the carbon and the other oxygen into a double bond. That counts as resonance.

[OwenSumter_2F]

Yeah, resonance structures are normally pretty redundant with large amounts of atoms, so it's pretty tricky to remember each atom you've used with double bonds and which you've haven't. Every individual atom gets a fair shot, not just the atom types.

[JonathanSung_2G]

I think one of the pointers I would give when drawing Lewis resonance structures is to understand the relationship between the octet rule and different atoms. In this example, I know that carbon has to satisfy the octet rule, so I will have to draw multiple resonance structures where the double bond is located between carbon and some other atom. In this case I can put the double bond between carbon and one oxygen, carbon and the other oxygen, and carbon and the nitrogen. The formal charge of an atom could be unfavorable in one resonance structure, and this is okay because it shows that that particular structure contributes less to the overall structure. Hope this helps!

[Vanessa Perez]

Hey yall! When choosing which resonance structure is least likely to contribute to the overall structure, would it be the Lewis Structure with the most charges? Or does this way of thinking not necessarily work all the time?

[Tanya Nguyen 1B]

How do you determine which structure contributes the most or least to the overall structure?