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Problem 2B3 7th Edition

Posted: Wed Jul 17, 2019 8:11 pm
by Danieljm1B
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?

Re: Problem 2B3 7th Edition

Posted: Wed Jul 17, 2019 10:51 pm
by Jeril Joseph 1B
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.

Re: Problem 2B3 7th Edition

Posted: Sat Jul 20, 2019 4:34 pm
by somyapanchal1D
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: