4.19 Predict shape of molecule

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

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Rachel Song 2A
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Joined: Fri Sep 25, 2015 3:00 am

4.19 Predict shape of molecule

Postby Rachel Song 2A » Sun Nov 29, 2015 10:40 pm

4.19 Predict the shapes and estimate the bond angles of (d) SnCl2.

Could someone please explain how to predict the shape of this moleculre? The answer key says it's angular but I thought it was linear. How would you draw the Lewis structure for this?

Roshni Kumar 1E
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: 4.19 Predict shape of molecule

Postby Roshni Kumar 1E » Sun Nov 29, 2015 10:53 pm

First thing you would do is count the valence of electrons. By looking at the periodic table, you see that Cl has 7 e- which in total would be 14 e- since it is Cl2; then add 4 e- for Sn making the total 18 e-. Then, draw the Lewis Structure for SnCl2 in which Sn would be the center with Cl attached it with single bonds. According to the octet rule, Cl and Sn need to achieve 8 e- however Sn isn't getting 8 e- from just the 2 Cl there would have to be 2 lone pairs on Sn making the shape of the molecule angular. I would say the best way of predicting the shape is by drawing the lewis structure.

MattDavid1d
Posts: 8
Joined: Thu Oct 01, 2015 3:00 am

Re: 4.19 Predict shape of molecule

Postby MattDavid1d » Sun Nov 29, 2015 11:55 pm

Draw the lewis structure and then determine how many regions of electron density are around the central atom, whether that be in bonds or lone pairs. You can then determine the AXE of the molecule, where X is the number of bonding pairs of electrons and E is the number of bonding pair. The result of the AXE formula will give you the shape of the molecule which you can then use to determine the bond angle(s).


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