Steps to Drawing a Lewis Structure

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Ariel Fern 2B
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Joined: Fri Aug 30, 2019 12:17 am

Steps to Drawing a Lewis Structure

Postby Ariel Fern 2B » Sun Nov 03, 2019 3:59 pm

Does anybody have like a "step by step" list in how they draw Lewis Structures? So far I feel like I'm all of over the place in terms of arranging atoms and assigning lone pairs. I always count valence electrons first, but if anybody has tips on the order they do stuff afterwards, that would be greatly helpful!

Anne Tsai 1F
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Joined: Thu Jul 25, 2019 12:15 am

Re: Steps to Drawing a Lewis Structure

Postby Anne Tsai 1F » Sun Nov 03, 2019 4:01 pm

I have trouble with drawing Lewis structures too, but I recall the UAs saying that the order we should follow is:

1. electrons
2. octet rule
3. formal charge

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Joined: Thu Jul 11, 2019 12:16 am

Re: Steps to Drawing a Lewis Structure

Postby JasonKwon_3k » Sun Nov 03, 2019 4:03 pm

1) count valence e- for each atom
2) determine the central atom (one with lowest ionization energy)
3) arrange atoms symmetrically around the central atom
4) assign the electron pairs

Megan Cao 1I
Posts: 103
Joined: Sat Sep 07, 2019 12:18 am

Re: Steps to Drawing a Lewis Structure

Postby Megan Cao 1I » Sun Nov 03, 2019 4:04 pm

I always count the number of electrons the molecule is supposed to have. be sure to consider if the molecule has a charge (1+, 1-, 2-, etc)
then, I use the most electronegative atom as the central atom.
this may seem extra, but I draw the dots of each atom around it's symbol because once I'm done I can see which electrons I can pair together.
always remember there's going to be at least one bond between atoms, so that usually gives you a start and from then you can figure out which remaining electrons will pair or not.
at the end I always recount the number of electrons and make sure the atoms have the lowest formal charge they can.

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Joined: Mon Sep 23, 2019 12:17 am

Re: Steps to Drawing a Lewis Structure

Postby JTijerina_4A » Sun Nov 03, 2019 4:04 pm

First you should count the valence electrons of each atom and sum them together so you have an idea of how many electrons you will be working with in your diagram. Be sure to add or subtract electrons if you are dealing with an ion. Then you should determine which atom can form the most bonds and use that as your central atom. Place the remaining atoms around your central atom and subtract the number of electrons you used in the form of bonds from your total. The remaining electrons should be used to fulfill the quartet rule for as many atoms as possible. Move lone pairs into bonds as necessary to fulfill the octet rule for all the atoms.

Caitlin Ciardelli 3E
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Joined: Wed Sep 18, 2019 12:19 am

Re: Steps to Drawing a Lewis Structure

Postby Caitlin Ciardelli 3E » Sun Nov 03, 2019 6:04 pm

When drawing Lewis Structures, I begin by totaling the number of valence electrons (remember to include extra or remove according to ion charges: cations and anions). Next, draw a beginning structure with the least electronegative atom in the middle, single bonds to each element, and fill the octet for however many electrons you have left over. From there, calculate formal charges and adjust your structure accordingly.

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Joined: Fri Aug 30, 2019 12:17 am

Re: Steps to Drawing a Lewis Structure

Postby AronCainBayot2K » Sun Nov 03, 2019 6:19 pm

First, count the amount of valence electrons. Second, determine what atom is most electronegative, this will be the central atom. Next, fill in bonds and dots based on the amount of electrons and the octet rule. Next, calculate the formal charges and keep manipulating bonds until you get the lowest possible charge.

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