## Formal Charge

$FC=V-(L+\frac{S}{2})$

Dustin Shin 2I
Posts: 34
Joined: Thu Sep 27, 2018 11:26 pm

### Formal Charge

When we need to draw Lewis structures or even resonance structures, do we need to show calculations done for formal charges in order not to miss points on exams? Will that ever be an issue? The last test asked to show full work so I am wondering if this is necessary.

WilliamNguyen_4L
Posts: 38
Joined: Thu Sep 27, 2018 11:28 pm

### Re: Formal Charge

Last test I just drew the most stable form of the lewis structure. I wrote all the calculations. If they ask for resonance then I think you should draw the resonance structures.

Sheridan Slaterbeck 1J
Posts: 33
Joined: Thu Sep 27, 2018 11:27 pm

### Re: Formal Charge

I think you should always show your calculations for formal charge, each TA grades differently but my TA said the more work you show the greater chance you will earn more points.

Luc Lorain 1L
Posts: 30
Joined: Thu Sep 27, 2018 11:18 pm

### Re: Formal Charge

For Lewis structures with equivalent resonance structures, I did the calculations for one of the structures, and put the appropriate formal charges around the other resonance forms. Otherwise, yeah you should do independent calculations for each resonance form.

Diana Sandoval 1K
Posts: 33
Joined: Thu Sep 27, 2018 11:25 pm

### Re: Formal Charge

WilliamNguyen_4D wrote:Last test I just drew the most stable form of the lewis structure. I wrote all the calculations. If they ask for resonance then I think you should draw the resonance structures.

What's the difference between the Lewis structure and the resonance structure?

AlyssaBei_1F
Posts: 63
Joined: Thu Sep 27, 2018 11:17 pm

### Re: Formal Charge

A resonance is a Lewis structure that have bonds in different equivalent locations.

Aleeque Marselian 1A
Posts: 36
Joined: Thu Sep 27, 2018 11:24 pm

### Re: Formal Charge

In my opinion, it is always better to show work just in case. Especially if the grader prefers to see the steps.

katie_sutton1B
Posts: 34
Joined: Thu Sep 27, 2018 11:17 pm

### Re: Formal Charge

It's obviously better if you do because of partial credit, but it's not necessary.

Arlene Linares 3A
Posts: 50
Joined: Thu Sep 27, 2018 11:25 pm

### Re: Formal Charge

How many points was the FC worth on the midterm?

uhedlund
Posts: 32
Joined: Wed Nov 15, 2017 3:03 am

### Re: Formal Charge

It is always better to show work just in case, but generally for formal charge I do not think it is necessary