Formal Charge

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

harperlacroix1a
Posts: 43
Joined: Fri Sep 28, 2018 12:19 am

Formal Charge

When determining molecular structures, is having the formal charge be 0 or having a complete octet more important?

Sabrina Ryu 3L
Posts: 30
Joined: Fri Sep 28, 2018 12:26 am

Re: Formal Charge

Formal charge is important in determining the Lewis Structure, which then allows us to determine the VSEPR model and the molecular shape!

Posts: 63
Joined: Fri Sep 28, 2018 12:19 am

Re: Formal Charge

It depends on whether or not an element can have an expanded octet. Some elements can only have eight electron so formal charge does not matter because you can't add electrons (however, you might be able to go to a double or triple bond), while others can improve their formal charge (closer to zero) by expanding their octet or increasing the number of bonds.

Eunice Lee 1A
Posts: 60
Joined: Wed Oct 03, 2018 12:16 am

Re: Formal Charge

Having zero as the formal charge on an atom is more important, as some elements don't completely follow the octet rule and can have more than eight valence electrons.

Samantha Chang 2K
Posts: 69
Joined: Fri Sep 28, 2018 12:17 am

Re: Formal Charge

Having a 0 formal charge is most important, unless it is an ion; therefore the formal charge has to be equal to the charge of the ion. Sometimes lewis dot structures can have expanded octet.

sarahartzell1A
Posts: 56
Joined: Fri Sep 28, 2018 12:17 am

Re: Formal Charge

It is important to pay attention to the formal charge as not all elements adhere to the octet rule.

pamcoronel1H
Posts: 45
Joined: Fri Sep 28, 2018 12:25 am

Re: Formal Charge

I believe formal charge is more important since, if its an ion, the formal charges of your Lewis structures have to match the ionization of the molecule. Also, when making your Lewis structure, you usually want a structure with a minimal amount of total charge. This means that the formal charge affects the structure, and the structure determines the molecular shape.

Jasmine Chow 1F
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 1 time

Re: Formal Charge

The formal charge is the best way to ensure your lewis structure is in the most stable state and to find its molecular shape via VSPER. Some ions may throw people off so formal charges are the best way to check your work.

Vicky Lu 1L
Posts: 60
Joined: Fri Sep 28, 2018 12:18 am

Re: Formal Charge

It is better to follow and determine molecular structures base on the formal charger as there are exceptions to the octet rule. Formal charge is the best way to make sure the Lewis structure is in the most stable state it can be as well as writing out the right Lewis structure since the formal charge of the atoms must add up to the formal charge of the overall molecule.

Megan Gianna Uy 3L
Posts: 30
Joined: Fri Sep 28, 2018 12:26 am

Re: Formal Charge

If an element is in row 3+ then it can have an expanded octet. However, formal charge is still important because it makes sure your lewis structure is in its most stable form, making it easier for you to identify the shape of the molecule.

Kevin Arokiaraj 4E
Posts: 18
Joined: Wed Nov 15, 2017 3:03 am

Re: Formal Charge

Since the octet rule is not universal, it's better to have the formal charge be 0.

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