### VSEPR

Posted:

**Sun Nov 17, 2019 6:25 pm**How is the VSEPR model used in determining shape? Is it also used in finding the angles?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=41&t=51914

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Posted: **Sun Nov 17, 2019 6:25 pm**

How is the VSEPR model used in determining shape? Is it also used in finding the angles?

Posted: **Sun Nov 17, 2019 6:33 pm**

He explained in class that we do not need to know the exact angles in the model, but we should know how the radii of atoms and other factors might impact the angles. Hope this helps.

Posted: **Sun Nov 17, 2019 7:36 pm**

The shape is always determined by the number of bonding pairs and lone pairs for the VSEPR model. And then once we determine the shape based on those things, we can also see the bond angles according to that shape.

Posted: **Sun Nov 17, 2019 7:52 pm**

The number of bonding pairs and lone pairs attached to a central atom determines its shape, I would recommend looking up a VSEPR chart as it shows how intuitive it is.

Posted: **Sun Nov 17, 2019 7:56 pm**

Use the VSEPR formula to determine the number of atoms and lone pairs in a molecule. Add up the Xs and the Es to determine the structure of the electrons (e.g. tetrahedral, octahedral, etc.), then remove as many atoms as there are Es to find the actual molecular shape. For example, tetrahedral molecular structures will always correspond to VSEPR formula AX4.

Posted: **Sun Nov 17, 2019 8:02 pm**

You will not need to know the exact angles of the models, you will only need to know the shape of the model. the VSEPR model has a specific notation that can help you figure the shape of the model. If you look up a VSEPR chart you can easily distinguish the shapes from the different models using the VSEPR notation.

VSEPR model notation:

A= central atom

X= bonded pair

E= lone pair

If you can find the VSEPR model notation it will be easier to find the shape.

VSEPR model notation:

A= central atom

X= bonded pair

E= lone pair

If you can find the VSEPR model notation it will be easier to find the shape.