2E.25

(Polar molecules, Non-polar molecules, etc.)

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mayarivers3I
Posts: 52
Joined: Wed Sep 18, 2019 12:18 am

2E.25

Postby mayarivers3I » Wed Nov 20, 2019 3:46 pm

The question is: Draw the Lewis structure and predict whether each of the following molecules is polar or nonpolar.

The molecule I am confused about is CH2Cl2 because I put the two hydrogens on opposite sides of the carbon atom and the two chlorines on the other two sides on the carbon, which cancels out the dipole moments, making the molecule nonpolar. Why is it that the lewis structure of CH2Cl2 doesn't have the hydrogen and chloride atoms on opposite sides? I was under the impression that electrons would try to be as far apart from each other, so this doesn't make sense.

Kavee Dodampahala 4E
Posts: 51
Joined: Sat Jul 20, 2019 12:17 am

Re: 2E.25

Postby Kavee Dodampahala 4E » Wed Nov 20, 2019 3:59 pm

I think it would help if you thought about the molecule in three dimensions. It would have a tetrahedral shape and so regardless of how the lewis structure is drawn, in real life, from any perspective, one side of the molecule would have the two hydrogens and the others would have the two chlorines, making it polar.

BeylemZ-1B
Posts: 95
Joined: Thu Jul 25, 2019 12:17 am

Re: 2E.25

Postby BeylemZ-1B » Wed Nov 20, 2019 4:07 pm

mayarivers3I wrote:The question is: Draw the Lewis structure and predict whether each of the following molecules is polar or nonpolar.

The molecule I am confused about is CH2Cl2 because I put the two hydrogens on opposite sides of the carbon atom and the two chlorines on the other two sides on the carbon, which cancels out the dipole moments, making the molecule nonpolar. Why is it that the lewis structure of CH2Cl2 doesn't have the hydrogen and chloride atoms on opposite sides? I was under the impression that electrons would try to be as far apart from each other, so this doesn't make sense.


When deciding polarity always remember to consider the model in 3D! Use the VSEPR shape and then it will become clear that the molecule is in fact non-polar.

RRahimtoola1I
Posts: 102
Joined: Fri Aug 09, 2019 12:15 am

Re: 2E.25

Postby RRahimtoola1I » Wed Nov 20, 2019 5:32 pm

Could you say that it would only be nonpolar if all the atoms around the central atom were the same?


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