## Determining Resonance

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

Samantha Rundle 3K
Posts: 22
Joined: Fri Sep 25, 2015 3:00 am

### Determining Resonance

Is there a quicker way to determine if there are resonance structures, other than calculating formal charge? If so, how?

Thanks!

HoganFenster2E
Posts: 23
Joined: Fri Sep 25, 2015 3:00 am

### Re: Determining Resonance

I think that you usually need to calculate the formal charges. It is a good way to check your work too, especially if the compound has a negative or positive charge, because it must have that charge. Also, a little shortcut is (I'm not sure how helpful this is) that whenever you have an Oxygen with a double bond and two lone pairs the charge will always be zero. You can also figure out when atoms will have a formal charge of zero and just memorize them. Thats what I do and it goes a little quicker.

Jessica Chern 1H
Posts: 22
Joined: Sat Jul 09, 2016 3:00 am

### Re: Determining Resonance

Also, if an atom is double bonded to one atom of a certain element X as well as single bonded to more atoms of that same element X (that aren't also bonded to anything else), there will be resonance.

Wang_Pong_Chan_1L
Posts: 10
Joined: Wed Sep 21, 2016 2:59 pm

### Re: Determining Resonance

First makes the octet on each of the elements, then using the electrons needed figure out the double bonds, which will show you whether there is resonance or not.