Formal charge purpose


Moderators: Chem_Mod, Chem_Admin

Moris 1H
Posts: 33
Joined: Fri Apr 06, 2018 11:01 am

Formal charge purpose

Postby Moris 1H » Sun May 13, 2018 5:05 pm

Why us calculating formal charge important for every Lewis Structure?

Jonghwee Park 1K
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

Re: Formal charge purpose

Postby Jonghwee Park 1K » Sun May 13, 2018 5:22 pm

I think it’s because of the formal charge adds up to 0, the Lewis structure is the most stable.

Heung Ching Chia 1E
Posts: 25
Joined: Mon Apr 09, 2018 1:38 pm

Re: Formal charge purpose

Postby Heung Ching Chia 1E » Sun May 13, 2018 5:57 pm

Yes, it is desirable for molecules to have the lowest energy lewis structure possible so that it can have the most stable structure. The lower the formal charge for the molecule overall and also for the individual atoms themselves, the more stable the structure.

Moris 1H
Posts: 33
Joined: Fri Apr 06, 2018 11:01 am

Re: Formal charge purpose

Postby Moris 1H » Sun May 13, 2018 6:31 pm

So once you make a basic lewis structure you would have to calculate the formal charges of each atoms in the structure and rearrange electrons to get to 0?

salvadoralvizo1J
Posts: 29
Joined: Fri Apr 06, 2018 11:01 am

Re: Formal charge purpose

Postby salvadoralvizo1J » Sun May 13, 2018 6:47 pm

If having a formal charge of 0 means that an atom is most stable, then why do atoms like chlorine tend to have a negative charge when isolated (ie Cl-)?

Amanda 1A
Posts: 31
Joined: Fri Apr 06, 2018 11:01 am

Re: Formal charge purpose

Postby Amanda 1A » Sun May 13, 2018 7:49 pm

yes, you would need to find the most stable bonding of that molecule by making the formal charges of the atoms zero or as close to zero as possible

Molly Oakes 1A
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

Re: Formal charge purpose

Postby Molly Oakes 1A » Sun May 13, 2018 8:18 pm

Making the formal charge as close to zero as possible determines the best Lewis structure.

Caitlyn Ponce 1L
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am
Been upvoted: 1 time

Re: Formal charge purpose

Postby Caitlyn Ponce 1L » Sun May 13, 2018 8:47 pm

Formal charge can also be used to check if your Lewis Structure is correct for charged molecules.

CarinaVargas1J
Posts: 20
Joined: Wed Nov 15, 2017 3:00 am

Re: Formal charge purpose

Postby CarinaVargas1J » Sun May 13, 2018 8:59 pm

Calculating the formal charge is important because if it adds up to 0, then the Lewis structure is the most stable.

victoria1l
Posts: 29
Joined: Fri Apr 06, 2018 11:05 am

Re: Formal charge purpose

Postby victoria1l » Sun May 13, 2018 9:13 pm

Instead of calculating the formal charge, could one simply make sure that all the atoms have the correct number of valence electrons ? or would this not work all the time?

Jada Larson 1F
Posts: 31
Joined: Fri Apr 06, 2018 11:03 am

Re: Formal charge purpose

Postby Jada Larson 1F » Sun May 13, 2018 9:34 pm

victoria1l wrote:Instead of calculating the formal charge, could one simply make sure that all the atoms have the correct number of valence electrons ? or would this not work all the time?


I believe that method would not work all of the time because some elements violate the octet rule. For instance, phosphorous holds up to 10 electrons and sulfur holds up to 12 electrons. (There are more exceptions than those I just mentioned.)

victoria1l
Posts: 29
Joined: Fri Apr 06, 2018 11:05 am

Re: Formal charge purpose

Postby victoria1l » Sun May 20, 2018 7:51 pm

Oh okay thank you !

victoria1l
Posts: 29
Joined: Fri Apr 06, 2018 11:05 am

Re: Formal charge purpose

Postby victoria1l » Sun May 20, 2018 7:53 pm

Is calculating the formal charge on a test necessary? will it be worth points?

Surya Palavali 1D
Posts: 24
Joined: Fri Apr 06, 2018 11:04 am

Re: Formal charge purpose

Postby Surya Palavali 1D » Sun May 20, 2018 8:35 pm

Because you always want the lowest formal charge possible in order to have the most stable Lewis Structure. I heard from my TA that it is possible you will have to calculate formal charges for points on either Test 3 or the final.

FizaBaloch1J
Posts: 41
Joined: Fri Apr 06, 2018 11:01 am

Re: Formal charge purpose

Postby FizaBaloch1J » Sun May 20, 2018 9:03 pm

This is because you are trying to find the most stable lewis structure for a molecular formula, and to do this you need to determine the formal charges of each resonance.

Amir Akhavan 1E
Posts: 34
Joined: Fri Apr 06, 2018 11:01 am

Re: Formal charge purpose

Postby Amir Akhavan 1E » Sun May 20, 2018 10:24 pm

The formal charge allows you to find the most stable form of the structure possible.

Garrett Dahn 1I
Posts: 28
Joined: Fri Apr 06, 2018 11:02 am
Been upvoted: 1 time

Re: Formal charge purpose

Postby Garrett Dahn 1I » Sun May 20, 2018 10:48 pm

If having a formal charge of 0 means that an atom is most stable, then why do atoms like chlorine tend to have a negative charge when isolated (ie Cl-)?


I'm not entirely sure I'm correct here, but I think the reason we usually write Cl as Cl- doesn't have to do with formal charge so much as the fact that Chlorine has seven valence electrons and therefore needs an additional electron to achieve a stable octet. Pure Chlorine with seven valence electrons (simply Cl) doesn't exist in nature because it is unstable. Instead, Chlorine is either bonded with another element (NaCl), itself (Cl2) or it exists as an anion (Cl-). It's the same reason Na is often denoted instead as Na+, since sodium exists in the world not as the unstable Na, but the cation Na+ or in a bonded molecule. It all has to do with ensuring that the version of Chlorine or Sodium we are dealing with is stable.

Hope this can be helpful!

AlyssaRivera
Posts: 29
Joined: Fri Apr 06, 2018 11:04 am

Re: Formal charge purpose

Postby AlyssaRivera » Sat May 26, 2018 9:52 pm

As Professor Lavelle has explained, you want to have the lewis structure in the most stable form. It's important to know what each individual elements charge is because it determines where the element should be placed in the structure.

victoria1l
Posts: 29
Joined: Fri Apr 06, 2018 11:05 am

Re: Formal charge purpose

Postby victoria1l » Sun Jun 03, 2018 10:39 pm

okay thanks!

Enzo_1I
Posts: 19
Joined: Fri Apr 06, 2018 11:02 am

Re: Formal charge purpose

Postby Enzo_1I » Sun Jun 03, 2018 10:52 pm

For a molecules lewis structure, it is best to find the most stable version. This is determined by finding the lowest energy of the molecule, which is just making the Formal charge equal to zero.

Miya Lopez 1I
Posts: 62
Joined: Tue Nov 14, 2017 3:00 am
Been upvoted: 1 time

Re: Formal charge purpose

Postby Miya Lopez 1I » Sun Jun 03, 2018 10:58 pm

If you had a molecule with three different lewis structures (resonance) and they had formal charges each with multiple zeros, would you pick the lewis structure with the most zeros/lowest formal charge to be the most stable lewis structure of that molecule?

Emilee Hosking 1D
Posts: 32
Joined: Fri Sep 28, 2018 12:17 am

Re: Formal charge purpose

Postby Emilee Hosking 1D » Tue Oct 30, 2018 7:52 pm

I believe that if there are multiple lewis structures that have an overall charge of 0, then it would just be a resonance right?

Elena Maneffa 1E
Posts: 33
Joined: Fri Sep 28, 2018 12:27 am
Been upvoted: 1 time

Re: Formal charge purpose

Postby Elena Maneffa 1E » Tue Oct 30, 2018 9:11 pm

Because of resonance, you can create various different structures of the same compound. But the version with the lowest formal charge is the most suitable. For this reason, we calculate formal charge.

Madeera_Mian_3B
Posts: 30
Joined: Fri Sep 28, 2018 12:24 am

Re: Formal charge purpose

Postby Madeera_Mian_3B » Wed Oct 31, 2018 6:37 pm

I agree with the responses, the goal is to get the formal charge to a minimum amount or 0. This is when the structure is most stable.

Kelly Zhang 1L
Posts: 31
Joined: Fri Sep 28, 2018 12:18 am

Re: Formal charge purpose

Postby Kelly Zhang 1L » Wed Oct 31, 2018 9:01 pm

why is the element most stable when its formal charge is 0?

Yukta Italia 3I
Posts: 31
Joined: Fri Sep 28, 2018 12:24 am

Re: Formal charge purpose

Postby Yukta Italia 3I » Thu Nov 01, 2018 1:03 pm

kellyzhang1210 wrote:why is the element most stable when its formal charge is 0?

When the formal charge of an element is 0, it's in the neutral state, which means that the amount of electrons is kind of "balanced" so that's why there is less instability.

Selina Bellin 2B
Posts: 62
Joined: Fri Sep 28, 2018 12:25 am

Re: Formal charge purpose

Postby Selina Bellin 2B » Thu Nov 01, 2018 3:02 pm

to determine the most stable formation

George Ghaly 2L
Posts: 66
Joined: Fri Sep 28, 2018 12:29 am
Been upvoted: 1 time

Re: Formal charge purpose

Postby George Ghaly 2L » Thu Nov 01, 2018 5:14 pm

Formal charge has to be considered when drawing lewis structures as it will help you figure out if there is a double bond or not while trying to figure out the most stable form of the compound.

Madelyn Romberg 3L
Posts: 29
Joined: Tue Oct 02, 2018 12:16 am

Re: Formal charge purpose

Postby Madelyn Romberg 3L » Thu Nov 01, 2018 9:58 pm

Calculating formal charges allows us to draw the most stable structure. For example, it will tell us if we should consider double bonds within the molecules to create more stability.

abbydouglas1K
Posts: 65
Joined: Fri Sep 28, 2018 12:26 am

Re: Formal charge purpose

Postby abbydouglas1K » Thu Nov 01, 2018 10:17 pm

How do we know when it is necessary to calculate the formal charge?

g orloff 1J
Posts: 45
Joined: Fri Sep 28, 2018 12:16 am

Re: Formal charge purpose

Postby g orloff 1J » Thu Nov 01, 2018 10:58 pm

formal charge allows us to determine which structure is the most stable when we draw it based on the available resonance structures.

Aidan Ryan 1B
Posts: 60
Joined: Fri Sep 28, 2018 12:17 am

Re: Formal charge purpose

Postby Aidan Ryan 1B » Thu Nov 01, 2018 11:08 pm

abbydouglas3J
The formal charge is to determine which lewis structure is the most accurate. Whichever has the closest value to 0 is what you use.

Sophia Fox 4B
Posts: 29
Joined: Fri Sep 28, 2018 12:27 am

Re: Formal charge purpose

Postby Sophia Fox 4B » Fri Nov 02, 2018 10:37 am

What does a non-zero formal charge mean, besides that the molecule isn't in its most stable state? Do the numbers actually mean anything?

Lopez_Melissa-Dis4E
Posts: 66
Joined: Fri Sep 28, 2018 12:20 am

Re: Formal charge purpose

Postby Lopez_Melissa-Dis4E » Fri Nov 02, 2018 11:06 am

Moris 1H wrote:Why us calculating formal charge important for every Lewis Structure?


Calculating the formal charge is important because when FC=0 that is when your structure is the most stable. That way you can verify that your structure is correct in terms of your placement of electrons.

John Liang 4G
Posts: 51
Joined: Fri Aug 30, 2019 12:18 am

Re: Formal charge purpose

Postby John Liang 4G » Sun Oct 27, 2019 10:07 pm

The formal charge is important to calculate in order to find out which lewis dot structure is most prevalent in nature, and therefore the most accurate.

abby hyman
Posts: 31
Joined: Thu Jul 25, 2019 12:16 am

Re: Formal charge purpose

Postby abby hyman » Sun Oct 27, 2019 10:10 pm

Formal charge indicates the gain or loss of electrons while forming covalent bonds. Used to find which is the most stable

Shail Avasthi 3C
Posts: 50
Joined: Fri Aug 30, 2019 12:17 am

Re: Formal charge purpose

Postby Shail Avasthi 3C » Sun Oct 27, 2019 10:23 pm

Formal charges also allow you to compare different possible lewis structures for the same molecule. For example, if the oxygen atoms in one lewis structure have positive formal charges and negative formal charges in another, the second lewis structure is probably preferable (assuming that other factors are taken into account) since oxygen is more electronegative than, say, carbon or nitrogen, and would rather have a negative formal charge than the aforementioned elements.

chrischyu4a
Posts: 47
Joined: Thu Jul 25, 2019 12:16 am

Re: Formal charge purpose

Postby chrischyu4a » Fri Nov 01, 2019 7:12 pm

A formal charge of 0 indicates that the molecule is at its most stable structure.

ashwathinair
Posts: 43
Joined: Sat Aug 17, 2019 12:17 am

Re: Formal charge purpose

Postby ashwathinair » Fri Nov 01, 2019 7:14 pm

Compounds naturally want to be at their most stable form. By using formal charges and equalling them to 0, we are better able to find what is ACTUALLY the most stable structure of the compound so that we know what the structure of the compound actually is in nature.

alex_4C
Posts: 44
Joined: Thu Sep 26, 2019 12:18 am

Re: Formal charge purpose

Postby alex_4C » Sun Nov 03, 2019 7:38 pm

On a test, will it specify that we need to calculate the formal charge or should we do it either way just to be sure?

Tahlia Mullins
Posts: 51
Joined: Thu Jul 25, 2019 12:15 am

Re: Formal charge purpose

Postby Tahlia Mullins » Sun Nov 03, 2019 7:43 pm

Especially when dealing with resonance, finding the formal charge of each lewis structure is essential to determining the most stable structure, with a formal charge of 0 or as close to 0 as possible.


Return to “Formal Charge and Oxidation Numbers”

Who is online

Users browsing this forum: No registered users and 1 guest