Problem 2B3 7th Edition

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Danieljm1B
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Joined: Mon Feb 25, 2019 12:15 am

Problem 2B3 7th Edition

Postby Danieljm1B » Wed Jul 17, 2019 8:11 pm

In the question, it asks to draw the Lewis structure of SiO2. I have the Solutions Manual on Chegg and on it, it shows that there are double bonds between the Si and each of the Oxygens. Can anyone explain to me why it's two double bonds instead of having the electrons drawn around the oxygens?

Jeril Joseph 1B
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Re: Problem 2B3 7th Edition

Postby Jeril Joseph 1B » Wed Jul 17, 2019 10:51 pm

So, we need to consider that this compound has a net charge of 0. When doing the Lewis structure, it would only make sense to give Si two double bonds to both O atoms since giving those Oxygens a double bond will make their formal charge 0. As to the electrons not being drawn on the Oxygens, I don't know what that means. there should be two lone pairs of electrons on each Oxygen. Silicon would have 0 lone pairs.

somyapanchal1D
Posts: 34
Joined: Mon Jun 17, 2019 7:23 am

Re: Problem 2B3 7th Edition

Postby somyapanchal1D » Sat Jul 20, 2019 4:34 pm

When trying to find the best lewis structure possible, you always have to account for the formal charge. The first possibility is to have two single bonded Si-O. The formal charge for each silicon and oxygen atom would come out as 2 and -1, respectively. The second possibility is to have two doubled bonded Si-O. The formal charge for each atom comes out as 0. Since you want to have the smallest formal charge possible, the structure with the double bond is the best representation of SiO2. Here is my work below if it helps:
Attachments
IMG_5165.JPG


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