Tips for completing Lewis Structures

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Jacinda Wollenweber 1D
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Joined: Wed Nov 16, 2016 3:02 am

Tips for completing Lewis Structures

Postby Jacinda Wollenweber 1D » Sat Jul 22, 2017 5:08 pm

Do any of you have any tips for drawing Lewis structures, particularly for more complex compounds such as glycine (chapter 3, question 41). The Lewis structure makes sense when looking at the answer but I want to know what steps they took to arrive at that answer. Hope you can help!

Kyle Sheu 1C
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Joined: Fri Jun 23, 2017 11:39 am

Re: Tips for completing Lewis Structures

Postby Kyle Sheu 1C » Sat Jul 22, 2017 8:53 pm

Amino acids follow the structure of a central C bonded to an amine (NH2), a carboxyl group (COOH), a H, and an R group. Without getting too deep into the biochemistry, we can essentially think of an R group as any group of C or H attached to the rest of the molecule. In the case of glycine, the simplest amino acid, the R group is H.

Timothy Kao 1B
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Joined: Fri Jun 23, 2017 11:39 am

Re: Tips for completing Lewis Structures

Postby Timothy Kao 1B » Sat Jul 22, 2017 9:31 pm

One thing I always make sure to remember is that usually the atom with the lowest electronegativity is the atom that becomes the central atom. I also tried memorizing which atoms had exceptions to the octet rule, such as Sulfur which can exceed an octet and Boron which can have an incomplete Octet, but the thing that I found most useful was practicing as many Lewis structure problems as I could.

Amy Wu 1D
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Joined: Fri Jun 23, 2017 11:39 am

Re: Tips for completing Lewis Structures

Postby Amy Wu 1D » Sun Jul 23, 2017 10:13 am

Timothy Kao 1B wrote:One thing I always make sure to remember is that usually the atom with the lowest electronegativity is the atom that becomes the central atom. I also tried memorizing which atoms had exceptions to the octet rule, such as Sulfur which can exceed an octet and Boron which can have an incomplete Octet, but the thing that I found most useful was practicing as many Lewis structure problems as I could.


Which atoms with exceptions to the octet rule will we be expected to know?

Timothy Kao 1B
Posts: 28
Joined: Fri Jun 23, 2017 11:39 am

Re: Tips for completing Lewis Structures

Postby Timothy Kao 1B » Mon Jul 24, 2017 9:08 am

Amy Wu 1D wrote:
Timothy Kao 1B wrote:One thing I always make sure to remember is that usually the atom with the lowest electronegativity is the atom that becomes the central atom. I also tried memorizing which atoms had exceptions to the octet rule, such as Sulfur which can exceed an octet and Boron which can have an incomplete Octet, but the thing that I found most useful was practicing as many Lewis structure problems as I could.


Which atoms with exceptions to the octet rule will we be expected to know?


I'm actually not sure. There's some listed in the lecture notes/course reader and in the textbook, but it left a lot out. I was planning on asking Professor Lavelle in class today.


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