How do I start a Lewis structure?

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

How do I start a Lewis structure?

Postby Jonghwee Park 1K » Sun May 20, 2018 11:55 pm

When I first start to draw a lewis structure, what should I first do to start the structure? I often get confused what element should be in the middle. Is there a way to know which is in the middle and what structure it will be? (for example, cyclic)

Gabi Landes 1-H
Posts: 31
Joined: Thu Feb 22, 2018 3:00 am

Re: How do I start a Lewis structure?

Postby Gabi Landes 1-H » Mon May 21, 2018 12:06 am

I would watch this Khan video, it goes through the steps for beginning the Lewis Structure! https://www.khanacademy.org/science/chemistry/chemical-bonds/copy-of-dot-structures/v/drawing-dot-structures

--> In general the least electronegative element goes in the middle!
--> Cyclic compounds = ring compound
(so a series of the atoms in a compound are all connected to form a ring)
Last edited by Gabi Landes 1-H on Mon May 21, 2018 12:13 am, edited 1 time in total.

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

Re: How do I start a Lewis structure?

Postby Heung Ching Chia 1E » Mon May 21, 2018 12:07 am

The least electronegative atom should be the central atom. You then draw the skeletal structure of the molecule by adding a single bond to connect all atoms in the molecule together. You then subtract this from the total number of valence electrons you have. You can then try to arrange the valence electrons as bonded pairs/lone pairs until you have no more electrons left. If that way does not work, you can try different ways of arranging the structure.

204750609
Posts: 18
Joined: Fri Apr 06, 2018 11:02 am

Re: How do I start a Lewis structure?

Postby 204750609 » Mon May 21, 2018 12:08 am

You should first calculate the total number of valence electrons then determine the least electronegative atom and make that your central atom. Hydrogen is never a central atom.


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