Drawing Lewis Structures

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Saachi_Kotia_4E
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Drawing Lewis Structures

Postby Saachi_Kotia_4E » Tue Oct 30, 2018 10:54 am

When drawing Lewis structures, how do you know where the atoms are? Like what angles the atoms are? Sometimes they're all in a straight line, but other times they're at 90 degree angles.

MaanasO 1A
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Joined: Fri Sep 28, 2018 12:26 am

Re: Drawing Lewis Structures

Postby MaanasO 1A » Tue Oct 30, 2018 4:16 pm

Hi Saachi!

So Lewis diagrams are based on how many atoms are bonded to a certain atom. CH4 has 4 hydrogen atoms bonded to the same carbon atom, so they'll look like a plus sign. We haven't done VSEPR models, so these diagrams don't actually represent how the molecule looks; they're just drawn that way for convenience.

Hope that helps!

Lia Inadomi 1I
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Joined: Fri Sep 28, 2018 12:15 am

Re: Drawing Lewis Structures

Postby Lia Inadomi 1I » Tue Oct 30, 2018 6:34 pm

Lewis structures are meant to represent where the electrons are and how the molecule is bonded, not an accurate visual representation

alanaarchbold
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Re: Drawing Lewis Structures

Postby alanaarchbold » Tue Oct 30, 2018 7:29 pm

Does resonance somehow affect the shape of structures?

Ava Kjos 1D
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Joined: Fri Sep 28, 2018 12:19 am

Re: Drawing Lewis Structures

Postby Ava Kjos 1D » Tue Oct 30, 2018 10:40 pm

No resonance won't affect the shape in the Lewis structures at all. To show resonance, you will need to draw multiple diagrams to show the different possibilities.

haleyervin7
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Re: Drawing Lewis Structures

Postby haleyervin7 » Thu Nov 01, 2018 2:06 pm

When drawing Lewis structures that aren’t symmetrical, like ONF, does it matter which side the O or F go on?

cristinapadilla_1E
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Re: Drawing Lewis Structures

Postby cristinapadilla_1E » Thu Nov 01, 2018 2:33 pm

When drawing Lewis structures, follow this format:
1) Count the number of valence electrons for each atom.
2) Count atom with lowest ionization energy as the central atom (H is never the central atom).
3) Arrange atoms symmetrically around central atom.
4) Calculate the formal charges so that they are as close to 0 as possible.
Exceptions:
- for cations, remove 1 electron for each +1 charge
- for anions, add 1 electron for each -1 charge

annabel 2A
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Re: Drawing Lewis Structures

Postby annabel 2A » Thu Nov 01, 2018 2:44 pm

How do we know how many resonance structures to draw?

abbydouglas1K
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Joined: Fri Sep 28, 2018 12:26 am

Re: Drawing Lewis Structures

Postby abbydouglas1K » Thu Nov 01, 2018 10:20 pm

annabel 1 1F wrote:How do we know how many resonance structures to draw?

I think you use the amount of possible double bonds between the same atoms to determine how many resonance structures you can have.

g orloff 1J
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Re: Drawing Lewis Structures

Postby g orloff 1J » Thu Nov 01, 2018 11:05 pm

the shape depends on the VESPR orientation which we haven't gone over yet but think about lone pairs as opposite charges so there is a positive side and negative side.

LeannaPhan14BDis1D
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Re: Drawing Lewis Structures

Postby LeannaPhan14BDis1D » Fri Nov 02, 2018 12:14 am

If the angles are determined by something we haven't gone over will we be tested and graded on specificity of our structures with those angles or will it not matter as much for this midterm.

Kelsey Li 3B
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Re: Drawing Lewis Structures

Postby Kelsey Li 3B » Fri Nov 02, 2018 12:09 pm

Since we didn't learn the VESPR orientation yet I don't think we need to worry about bond angles. What's most important is just making sure when you draw your lewis dot structure that it's drawn evenly. The lewis dot structure just represent where the electrons are and the type of bonds but we don't need to worry about the precise bond angles.

taywebb
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Joined: Fri Sep 28, 2018 12:15 am

Re: Drawing Lewis Structures

Postby taywebb » Fri Nov 02, 2018 2:26 pm

Can anyone confirm my understanding of ionic and covalent bonding in regards to lewis structures? I believe that when you have an ion you use ionic bonding with the brackets and if the atoms are a neutral charge you use covalent bonding? Is there anything more specific to drawing these diagrams?

SummerLee1F
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Joined: Fri Sep 28, 2018 12:16 am

Re: Drawing Lewis Structures

Postby SummerLee1F » Sat Nov 03, 2018 7:33 pm

annabel 1 1F wrote:How do we know how many resonance structures to draw?


You just draw all of the possibilities of each bond. Example, let’s say there’s two H’s and one O. One H & O have a double bond. For the second resonance structure, you would just draw the double bond on the other H instead of the first one.

804994652
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Joined: Fri Sep 28, 2018 12:26 am

Re: Drawing Lewis Structures

Postby 804994652 » Sun Nov 04, 2018 10:00 am

I'm still confused about the arrangement about the atoms. For examples TB (7th ed) 2C.3c says to draw the lewis structure of HClO3 and I arranged the atoms of oxygen and hydrogen around Cl. The solution manual put the H connected to the Oxygen instead. How would I have known to do this?


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