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Formal Charge

Posted: Wed Nov 14, 2018 12:52 pm
by Rebecca Altshuler 1D
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?

Re: Formal Charge

Posted: Wed Nov 14, 2018 12:56 pm
by taline_n
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.

Re: Formal Charge

Posted: Wed Nov 14, 2018 2:16 pm
by marisaimbroane1J
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.

Re: Formal Charge

Posted: Wed Nov 14, 2018 2:20 pm
by dgerges 4H
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

Re: Formal Charge

Posted: Wed Nov 14, 2018 2:53 pm
by Sameen Mahmood 3D
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.

Re: Formal Charge

Posted: Wed Nov 14, 2018 3:26 pm
by Shash Khemka 1K
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!

Re: Formal Charge

Posted: Wed Nov 14, 2018 3:49 pm
by Nawaphan Watanasirisuk 3B
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.

Re: Formal Charge

Posted: Wed Nov 14, 2018 4:39 pm
by duenezjuleny1D
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!

Re: Formal Charge

Posted: Wed Nov 14, 2018 4:47 pm
by yea-lyn pak_1G
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).

Re: Formal Charge

Posted: Sun Nov 18, 2018 4:28 pm
by kimberlyrose1G
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

Re: Formal Charge

Posted: Sun Dec 02, 2018 8:01 pm
by Tony Chung 2I
you typically want the formal charge to be 0

Re: Formal Charge

Posted: Sun Dec 02, 2018 10:21 pm
by Luis_Yepez_1F
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.

Re: Formal Charge

Posted: Fri Oct 25, 2019 11:12 am
by Shutong Hou_1F
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.

Re: Formal Charge

Posted: Sat Oct 26, 2019 5:44 pm
by Viviana Velasquez
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.