Formal Charge of the Same Element


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Bailey Giovanoli 1L
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Formal Charge of the Same Element

Postby Bailey Giovanoli 1L » Thu Nov 05, 2020 10:53 pm

Within a Lewis Structure, will the formal charge of an atom of that element always be the same? This will always be the same, regardless of different bond types, right? For Example in CO3 with a -2 charge, all of the oxygen atoms will have a formal charge of -1, regardless of one of the oxygens having a double bond instead of a single bond. Is this the right idea, or is the formal charge of oxygen in this case just a coincidence?

Claire_Latendresse_1E
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Re: Formal Charge of the Same Element

Postby Claire_Latendresse_1E » Thu Nov 05, 2020 11:08 pm

Each atom gets its own formal charge, even if it is the same element as another one in the molecule. In CO3^2-, all of the oxygen atoms have an FC of -1, but that is a coincidence. An example of two oxygen atoms having a different FC in the same molecule would be nitrite, NO2-, where the oxygen with a single bond has an FC of -1 and the oxygen with a double bond has an FC of 0.

Anil Chaganti 3L
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Re: Formal Charge of the Same Element

Postby Anil Chaganti 3L » Fri Nov 06, 2020 11:29 pm

Adding onto what the previous person stated, formal charge refers to the number of valence minus the number of bonds divided by 2 and the number of nonbonding electrons (the dots). Each atom gets its individual charge according to the number of bonds there are and valence electrons there are. Therefore, it does differ depending on the bond type (double or single).

Jason_John_2F
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Re: Formal Charge of the Same Element

Postby Jason_John_2F » Sat Nov 07, 2020 2:02 pm

i agree each atom in a molecule has its own formal charge

Q Scarborough 1b
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Re: Formal Charge of the Same Element

Postby Q Scarborough 1b » Sat Nov 07, 2020 2:13 pm

Each atom has its own formal charge, and the summation of them give you to total formal charge

Ryan Agcaoili 2E
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Re: Formal Charge of the Same Element

Postby Ryan Agcaoili 2E » Sat Nov 07, 2020 2:16 pm

I believe that each atom should have its own formal charge because each atom on the compound can have different numbers of bonds and valence electrons.

SLai_1I
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Re: Formal Charge of the Same Element

Postby SLai_1I » Sat Nov 07, 2020 2:16 pm

No, as each reply has stated, each atom has its own formal charge. Even though there could be 2 of the same element in a lewis structure, their formal charges are dependent on the amount of bonds and lone pairs they are connected to. This could result in 2 atoms of the same element having different formal charges.

Emma Strassner 1J
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Re: Formal Charge of the Same Element

Postby Emma Strassner 1J » Sat Nov 07, 2020 3:41 pm

I agree with what has been said about each atom having its own formal charge. It all depends on the individual bonds and lone pairs that accompany each atom, which determines the charge.

Kyla Roche 2K
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Re: Formal Charge of the Same Element

Postby Kyla Roche 2K » Sat Nov 07, 2020 6:27 pm

The different number of bonds and valence electrons causes atoms in a compound to have different formal charges. The sum of all formal charges equals the total charge.

Akriti Ratti 1H
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Re: Formal Charge of the Same Element

Postby Akriti Ratti 1H » Sat Nov 07, 2020 7:06 pm

Hi! Each atom has its own formal charge that is dependent on the number of bonds and valence electrons.

Eric Cruz 2G
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Re: Formal Charge of the Same Element

Postby Eric Cruz 2G » Sat Nov 07, 2020 11:21 pm

The formal charge is different for each atom in each molecule. In additional, the formal charge can change based on the number of bonds. So no, oxygen will not always have a formal charge of -1. It could in fact have a formal charge of 0. For example in NO3-, there is an oxygen with a double bond with Nitrogen and the two other oxygens have a single bond with nitrogen. Therefore, even within the same molecule, these oxygens have different formal charge. The double bond oxygen would have 4 lone pair electrons and 4 paired electrons. This would give the double bond oxygen a formal charge of 6-4-(4/2)=0 and give the single bond oxygen 6-6-2/2=-1

Sydney Jensen 3L
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Re: Formal Charge of the Same Element

Postby Sydney Jensen 3L » Sun Nov 08, 2020 12:23 pm

The formal charge varies, and it depends on the amount of bonds and valence electrons that are present.

Serena Song 1A
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Re: Formal Charge of the Same Element

Postby Serena Song 1A » Sun Nov 08, 2020 12:57 pm

The formal charge of an element can vary, even within the same molecule. A great example of this is resonance structures, such as nitrite (NO2^-). In the lewis structure of nitrite, one of the oxygen has 3 lone pairs and a single bond with nitrogen, giving it a formal charge of -1. The other oxygen has 2 lone pairs and a double bond of nitrogen, giving it a formal charge of 0. Depending on the number of lone pairs and bonded pairs of electrons the element has, the formal charge can change.

Bailey Giovanoli 1L
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Re: Formal Charge of the Same Element

Postby Bailey Giovanoli 1L » Sun Nov 08, 2020 1:50 pm

Thanks, everyone! I found this very helpful. I figured out I had a calculation error on the one I was doing, so it makes sense why I wasn't approaching the problem correctly conceptually.

Gerardo Ortega 2F
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Re: Formal Charge of the Same Element

Postby Gerardo Ortega 2F » Sun Nov 08, 2020 2:03 pm

The formal charge can be different in some cases. For example, in Dr. Lavelle's lecture 14, he adds 2 more covalent bonds to the central atom S in SO4(2-). Adding more covalent bonds to the central atom made the formal charge of 2 Oxygen atoms 0 while the other 2 remained -1.

Tatyana Bonnet 2H
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Re: Formal Charge of the Same Element

Postby Tatyana Bonnet 2H » Sun Nov 08, 2020 2:23 pm

The formal charge of the same element can differ based on the amount of bonds it has and the number of valence electrons as those numbers would result in varying charges when plugged into the formal charge formula. To be safe try to find the formal charge of all atoms of the element, even if they are the same, to see if you can come up with the same overall charge of the molecule given.


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