Best way to go about drawing Lewis structures

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Jasmine 2C
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Joined: Wed Sep 18, 2019 12:18 am

Best way to go about drawing Lewis structures

Postby Jasmine 2C » Fri Nov 01, 2019 2:03 am

So is the best way to draw Lewis structures is 1) count all valence e- 2) choose atom with lowest ionization energy as central atom 3) arrange the rest of the atoms around the central atom 4) draw covalent bonds and unpaired e- that adds up to the number in Step 1 5) calculate the formal charges to make sure the net charge is correct and 6) if necessary, edit the amount of covalent bonds if the formal charges are incorrect?
So essentially, drawing the structure is like a trial and error process?
If anyone has a better method, please explain!

andrewcj 2C
Posts: 102
Joined: Thu Jul 11, 2019 12:17 am

Re: Best way to go about drawing Lewis structures

Postby andrewcj 2C » Fri Nov 01, 2019 3:04 am

I suppose the trial and error gets easier with experience, as it is possible to identify patterns such as certain functional groups or complex ions in a structure.

SGonzales_3L
Posts: 55
Joined: Thu Jul 11, 2019 12:17 am

Re: Best way to go about drawing Lewis structures

Postby SGonzales_3L » Fri Nov 01, 2019 9:45 am

I think this is the best way to go about it. I also do the same thing and change my Lewis structures as necessary. One thing I've found to be helpful is to divide the total electron count by 2 to find the number of electron pairs. This just allows me to count how many bonded atoms/lone pairs there will be in the molecule and prevents me from making mistakes in counting each and every electron.

Sartaj Bal 1J
Posts: 101
Joined: Thu Jul 25, 2019 12:17 am

Re: Best way to go about drawing Lewis structures

Postby Sartaj Bal 1J » Fri Nov 01, 2019 10:10 am

This is all great! Also, for formal charges, I would make sure that the negative charges are on the most electronegative atom of the molecule. This because these atoms have a higher affinity for electrons in comparison to others.

Jessica Tran_3K
Posts: 50
Joined: Thu Jul 25, 2019 12:17 am

Re: Best way to go about drawing Lewis structures

Postby Jessica Tran_3K » Fri Nov 01, 2019 10:25 am

I also think this is the best way to go about it. I usually do trial and error, and as I get used to drawing lewis structures, I can kind of predict/tell how to draw the structures/remember what it's supposed to look like if I've drawn it before.

Qilan Li 4I
Posts: 54
Joined: Mon Jun 17, 2019 7:23 am

Re: Best way to go about drawing Lewis structures

Postby Qilan Li 4I » Fri Nov 01, 2019 10:33 am

Your way is the process that I use when I draw Lewis structures. I also think as you draw more and more, you get used to it and begin to remember how certain structures look like. The two tips commented under this post are also very helpful.

Julia Mazzucato 4D
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Joined: Fri Aug 30, 2019 12:17 am

Re: Best way to go about drawing Lewis structures

Postby Julia Mazzucato 4D » Fri Nov 01, 2019 5:11 pm

Yes, that process will generally get you the correct result. I think a lot of it is just building an intuition around knowing where to place each atom/bond, which gets easier with practice. It's harder when you're doing Lewis structures for a compound consistent of multiple polyatomic ions like H2CNH2COOH. I generally like to keep the atoms from the polyatomic ions bound to eachother within the lewis dot structure and I'd say like 75% of the time this gets me the correct result pretty quickly. But yeah, trial and error.

Jasmine 2C
Posts: 184
Joined: Wed Sep 18, 2019 12:18 am

Re: Best way to go about drawing Lewis structures

Postby Jasmine 2C » Sun Nov 03, 2019 9:14 pm

Thanks for the help! Nice to know that everyone is doing trial and error like me.


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