Lewis Structures

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Abigail Menchaca_1H
Posts: 104
Joined: Sat Sep 07, 2019 12:19 am

Lewis Structures

Postby Abigail Menchaca_1H » Sun Nov 03, 2019 11:47 pm

How would I know when it is right to use a double bond or triple bond? For example CO

Maya Serota 3G
Posts: 53
Joined: Tue Sep 24, 2019 12:17 am

Re: Lewis Structures

Postby Maya Serota 3G » Sun Nov 03, 2019 11:48 pm

You want to construct the bonds based on which structure results in the formal charges of each atom being closest to zero (unless you want a certain charge on the molecule)

Megan Vu 1J
Posts: 101
Joined: Thu Jul 25, 2019 12:15 am

Re: Lewis Structures

Postby Megan Vu 1J » Mon Nov 04, 2019 2:10 pm

First, you have to count the number of valence electrons in the molecule. For example, for CO, it would have 10 total electrons.
Then, since it's CO, it would have a shared single bond totaling to 8 e-. Because it needs to have the octet rule for each atom, this is not enough to satisfy the octet rule from lone pairs. Instead, you should have a double bond. Here, it also does not satisfy the octet rule, and the final form should be a triple bond. When there's a triple bond, there's 4 electrons left over which can be put as lone pairs on both C and O.

You should also later check the formal charges in order to get the most stable Lewis Structure.

Posts: 51
Joined: Sat Aug 24, 2019 12:16 am

Re: Lewis Structures

Postby RoshniVarmaDis1K » Mon Nov 04, 2019 2:25 pm

Assign double and triple bonds to satisfy the octet rule and reduce formal charge.

It may be helpful to keep in mind that C usually forms four bonds, N usually forms three, and O usually forms two.

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