Formal Charge

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Rebecca Altshuler 1D
Posts: 61
Joined: Fri Sep 28, 2018 12:15 am

Formal Charge

Postby Rebecca Altshuler 1D » Wed Nov 14, 2018 12:52 pm

When making a Lewis structure for an ion, does it matter what atom the formal charge is on, or the structure is valid as long as the overall formal charge is correct?

taline_n
Posts: 64
Joined: Fri Sep 28, 2018 12:17 am

Re: Formal Charge

Postby taline_n » Wed Nov 14, 2018 12:56 pm

Ideally, a nonzero formal charge should be located on the outer atoms rather than the central atom. If there's no way of avoiding a formal charge on the central atom, it should be the smallest nonzero formal charge out of all the atoms in the compound.

marisaimbroane1J
Posts: 69
Joined: Fri Sep 28, 2018 12:23 am

Re: Formal Charge

Postby marisaimbroane1J » Wed Nov 14, 2018 2:16 pm

If it is not possible for all atoms to have a zero formal charge, make sure that atoms (like oxygen) that are more electronegative have a negative charge. An atom like oxygen should never have a positive formal charge; it would never exist in that state.

dgerges 4H
Posts: 65
Joined: Fri Sep 28, 2018 12:24 am

Re: Formal Charge

Postby dgerges 4H » Wed Nov 14, 2018 2:20 pm

It should also be noted that certain atoms like Carbon almost always need to have a formal charge of zero to maintain it's stability

Sameen Mahmood 3D
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Joined: Wed Jun 13, 2018 3:00 am

Re: Formal Charge

Postby Sameen Mahmood 3D » Wed Nov 14, 2018 2:53 pm

It does matter what formal charges the atoms have because you are always looking for the most ideal/stable structure. In general, more electronegative atoms should have negative formal charges as opposed to less electronegative ones. Granted, you would want them all to be zero ideally, but if the overall charge of the molecule is say -1 and you have [BrO3]-, O is more electronegative than Br so you would want it to have a negative formal charge, not Br, while keeping all of the other atoms at 0 or as close to 0 as possible.

Shash Khemka 1K
Posts: 38
Joined: Fri Sep 28, 2018 12:18 am

Re: Formal Charge

Postby Shash Khemka 1K » Wed Nov 14, 2018 3:26 pm

An ion will never have an overall formal charge of 0. It is ideal to put the disbalance on the outer atoms to have a more stable Lewis Structure. Hope this helped out!

Nawaphan Watanasirisuk 3B
Posts: 58
Joined: Tue Nov 28, 2017 3:03 am

Re: Formal Charge

Postby Nawaphan Watanasirisuk 3B » Wed Nov 14, 2018 3:49 pm

Negative charge should be on the more electronegative atom such as oxygen and positive charge should be on the less electronegative atom. However this comes seconds to filling up octets or getting the overall charge to 0.

duenezjuleny1D
Posts: 48
Joined: Fri Sep 28, 2018 12:24 am

Re: Formal Charge

Postby duenezjuleny1D » Wed Nov 14, 2018 4:39 pm

Ideally, you would like all of your ions to have a formal charge/overall charge of 0 but you will always be looking for the most stable structure possible!

yea-lyn pak_1G
Posts: 30
Joined: Fri Sep 28, 2018 12:18 am

Re: Formal Charge

Postby yea-lyn pak_1G » Wed Nov 14, 2018 4:47 pm

There are multiple structures that will get you the same, correct overall charge. Thus, you want the structure that has the most 0 formal charges as possible (because this ensures the most stability). If there is a negative formal charge on an atom, it should be on the most electronegative atoms (like oxygen is more likely to have a negative formal charge than carbon is).

kimberlyrose1G
Posts: 44
Joined: Fri Sep 28, 2018 12:27 am

Re: Formal Charge

Postby kimberlyrose1G » Sun Nov 18, 2018 4:28 pm

the formal charge that is not equal to zero should not be on the central atom (as it makes the molecule very unstable), and should ideally be on the outer atom that is most/more electronegative

Tony Chung 2I
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: Formal Charge

Postby Tony Chung 2I » Sun Dec 02, 2018 8:01 pm

you typically want the formal charge to be 0

Luis_Yepez_1F
Posts: 50
Joined: Fri Sep 28, 2018 12:18 am

Re: Formal Charge

Postby Luis_Yepez_1F » Sun Dec 02, 2018 10:21 pm

Since it is an ion, the overall FC should not be equal to zero. Ideally, you want the central atom to have an FC=0 and have any charge whether positive or negative on the outer atoms around the central atom.

Shutong Hou_3I
Posts: 53
Joined: Sat Sep 14, 2019 12:17 am

Re: Formal Charge

Postby Shutong Hou_3I » Fri Oct 25, 2019 11:12 am

Yes, it matters. The most ideal situation is to have 0 formal charges on each atom. If it cannot be 0, then it is best to have the least absolute sum value of formal charges with the most negative on the most electronegative element.

Viviana Velasquez
Posts: 41
Joined: Sat Jul 20, 2019 12:15 am

Re: Formal Charge

Postby Viviana Velasquez » Sat Oct 26, 2019 5:44 pm

Usually, you want the central atom to be the one with the formal charge of 0 if it is not possible for all atoms to have a formal charge of zero.


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