Naming the Shape

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

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Raquel Rodriguez
Posts: 68
Joined: Fri Sep 28, 2018 12:26 am

Naming the Shape

Postby Raquel Rodriguez » Mon Nov 19, 2018 12:01 am

What is one way it is easy to remember the different shape names for Lewis structure?

mahika_nayak_3L
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

Re: Naming the Shape

Postby mahika_nayak_3L » Mon Nov 19, 2018 12:07 am

Generally, try to visualize the structure based on the number of bonded pairs and lone pairs. You can guess some structures from the name, eg. trigonal planar or trigonal pyramidal, but for the most part you should try to memorize the common ones. Here is a chart for your reference: https://images.tutorvista.com/cms/image ... chart1.png.

Carlos Gomez 3H
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Joined: Fri Sep 28, 2018 12:25 am

Re: Naming the Shape

Postby Carlos Gomez 3H » Mon Nov 19, 2018 12:58 am

I think it is best to memorize all of the possible shapes and it would possibly help to also understand which shapes can be made from the different electron arrangements, such as an electron arrangement of trigonal planar can lead to an angular molecular shape if I am not mistaken. Just little connections like that would help.

Sapna Ramappa 1J
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Joined: Fri Sep 28, 2018 12:24 am

Re: Naming the Shape

Postby Sapna Ramappa 1J » Mon Nov 19, 2018 8:12 am

Personally, I think that visualizing the shapes really allowed me to memorize the names of them. If you're a visual learner, there are many charts online that might help elucidate the connection between number of bonds, number of lone pairs, shapes, and the names of the shapes. One example is this chart: https://chemstuff.co.uk/academic-work/a ... molecules/

Raquel Rodriguez
Posts: 68
Joined: Fri Sep 28, 2018 12:26 am

Re: Naming the Shape

Postby Raquel Rodriguez » Sat Nov 24, 2018 6:13 pm

Thank you for the links.

Ruiting Jia 4D
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Re: Naming the Shape

Postby Ruiting Jia 4D » Sat Nov 24, 2018 9:52 pm

With the shapes, do we need to memorize the bond angles?

yaosamantha4F
Posts: 31
Joined: Fri Sep 28, 2018 12:29 am

Re: Naming the Shape

Postby yaosamantha4F » Sat Nov 24, 2018 11:05 pm

I think it's helpful but not 100% necessary to memorize the bond angles, since you can usually determine them by visualizing the shape.

RoopshaChatterjee 1G
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Joined: Fri Sep 28, 2018 12:17 am

Re: Naming the Shape

Postby RoopshaChatterjee 1G » Sun Nov 25, 2018 1:03 pm

I think we have to memorize the bond angles for the structures we were shown in class. I believe we're also expected to know how the angles are affected by lone pairs.

305127455
Posts: 30
Joined: Fri Sep 28, 2018 12:16 am

Re: Naming the Shape

Postby 305127455 » Sun Nov 25, 2018 7:42 pm

Ruiting Jia 4D wrote:With the shapes, do we need to memorize the bond angles?

I think we only need to remember those basic ones, such as 109.5˚, and how change in structure (like adding lone-pair electrons) can affect them.

ThomascnguyenDis1J
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Joined: Fri Sep 28, 2018 12:16 am

Re: Naming the Shape

Postby ThomascnguyenDis1J » Sun Nov 25, 2018 8:12 pm

Will we ever be told to draw out the vsepr model for a molecule?

Rebecca Park
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Joined: Fri Sep 28, 2018 12:17 am

Re: Naming the Shape

Postby Rebecca Park » Sun Nov 25, 2018 8:17 pm

I think I remember him saying that we won't have to draw it, but I'm not completely sure.

Esther Lee 4H
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Joined: Fri Sep 28, 2018 12:29 am

Re: Naming the Shape

Postby Esther Lee 4H » Sun Nov 25, 2018 8:18 pm

mahika_nayak_3L wrote:Generally, try to visualize the structure based on the number of bonded pairs and lone pairs. You can guess some structures from the name, eg. trigonal planar or trigonal pyramidal, but for the most part you should try to memorize the common ones. Here is a chart for your reference: https://images.tutorvista.com/cms/image ... chart1.png.

thank you for the link!

Pritish Patil 1K
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

Re: Naming the Shape

Postby Pritish Patil 1K » Sun Nov 25, 2018 10:05 pm

I don't think we are required to draw the VSEPR model.

yuetao4k
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Joined: Fri Sep 28, 2018 12:27 am
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Re: Naming the Shape

Postby yuetao4k » Sun Nov 25, 2018 10:08 pm

There are charts that are organised in a specific way that can help with memorizing. You can google molecular shapes and be able to find a chart!

Julia Lee
Posts: 80
Joined: Fri Sep 28, 2018 12:29 am

Re: Naming the Shape

Postby Julia Lee » Sun Nov 25, 2018 10:11 pm

the chart in the textbook is actually really helpful. As long as you can visualize it, it will be easy to remember the shapes and bond angles.
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Louise Zhuang
Posts: 31
Joined: Fri Sep 28, 2018 12:28 am

Re: Naming the Shape

Postby Louise Zhuang » Sun Nov 25, 2018 10:28 pm

You can remember them by each electron geometries. For instance, start with AX6, which is octahedral in both electron and molecular geometry. Then replace one atom with lone pair(AX5E, which is square pyramidal, etc

Andreana Vetus 1A
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Joined: Fri Sep 28, 2018 12:17 am

Re: Naming the Shape

Postby Andreana Vetus 1A » Sun Nov 25, 2018 10:30 pm

Ruiting Jia 4D wrote:With the shapes, do we need to memorize the bond angles?


Exact angles in the presence of lone pairs would be determined experimentally, so you may not need to know those. But you do need to memorize the set angles, and when they become "slightly less" and "extremely less" than other angles.


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