Formal Charge

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Ashley Lopez 3J
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Joined: Wed Sep 30, 2020 10:06 pm

Formal Charge

Postby Ashley Lopez 3J » Sun Nov 15, 2020 5:21 pm

When doing formal charges, do we know it is at the best Lewis structure when the atom with the least electronegativity (the atom in the middle) equals 0? Is that an indication that we could stop or do we just kind of stop when the formal charges of everything is at its lowest?

Sara_Lim_2C
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Joined: Wed Sep 30, 2020 9:55 pm

Re: Formal Charge

Postby Sara_Lim_2C » Sun Nov 15, 2020 5:25 pm

From my knowledge, the least electronegative atom doesn't need to be at 0, but it just shouldn't be negative. I think a good rule of thumb is to stop whenever the formal charges and total charge are at the lowest they can be without the least electronegative atom being negative.

I could be completely wrong though, so if I am someone please correct me!

Christine Ma 3L
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Re: Formal Charge

Postby Christine Ma 3L » Sun Nov 15, 2020 5:26 pm

I think we stop when all the charges are as close to 0 as we can get them. Because energy is required when there's charge separation of any kind (+ or - FC), getting as many formal charges to zero as possible should be the goal since FC=0 is the most stable. If I'm wrong, please correct me!

Also to the above poster, I think a negative FC would be alright since Boron has a negative FC when it reacts to have 4 bonds, so it's case-dependent.

Kyla Roche 2K
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Joined: Wed Sep 30, 2020 9:59 pm

Re: Formal Charge

Postby Kyla Roche 2K » Sun Nov 15, 2020 5:45 pm

Yes, just try to get each atom to have a formal charge of zero or as close to zero as possible because this makes the molecule more stable and less reactive.

Logan Wiedemann 3J
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Joined: Wed Sep 30, 2020 9:59 pm

Re: Formal Charge

Postby Logan Wiedemann 3J » Sun Nov 15, 2020 5:45 pm

Hi! The atom doesn't have to be right at zero, but typically the best one to use is the one that has the charges closest to zero as you can get them as these are the most accurate. I hope this helped!!

Ansh Patel 2I
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Joined: Wed Sep 30, 2020 9:42 pm

Re: Formal Charge

Postby Ansh Patel 2I » Sun Nov 15, 2020 6:18 pm

Hi! I believe you are right in that the goal is to get the central atom to have a formal charge of zero or as close to zero as possible because this would indicate a much more stable molecule.

Haochen He 3L
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Re: Formal Charge

Postby Haochen He 3L » Sun Nov 15, 2020 6:25 pm

Hi! I think you are right about getting each atom equal or close to 0 formal charge.

Andrew Yoon 3L
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Joined: Wed Sep 30, 2020 9:36 pm

Re: Formal Charge

Postby Andrew Yoon 3L » Sun Nov 15, 2020 7:00 pm

Yes the more stable molecule/better lewis structure would be when the central atom has a formal charge that is or very close to zero.

Andrew Yoon 3L
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Joined: Wed Sep 30, 2020 9:36 pm

Re: Formal Charge

Postby Andrew Yoon 3L » Sun Nov 15, 2020 7:00 pm

Yes the more stable molecule/better lewis structure would be when the central atom has a formal charge that is or very close to zero.

Isabella Cortes 2H
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Re: Formal Charge

Postby Isabella Cortes 2H » Sun Nov 15, 2020 7:31 pm

when drawing lewis structures, I believe that its best when the central atom has a formal charge thats either 0 or close to it.

Mina Tadros 3L
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Joined: Wed Sep 30, 2020 9:38 pm

Re: Formal Charge

Postby Mina Tadros 3L » Sun Nov 15, 2020 7:35 pm

The most stable structure would be the one with the atoms having a formal charge closest to 0. Also, you should always make sure that the most electronegative atom holds the negative formal charge since it is the most capable of holding the electrons. If the most electronegative atom has a + formal charge, it is highly unstable and not a plausible structure.

Arnav Saud 2C
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Joined: Wed Sep 30, 2020 9:51 pm

Re: Formal Charge

Postby Arnav Saud 2C » Sun Nov 15, 2020 8:39 pm

The goal on formal charges is maximizing the number of atoms in a molecule with 0, and to get positive charges on the least electronegative atoms in the structure and negative chares on the most electronegative atoms.


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