VSEPR formula

[205389184]

If we are able to determine the shape of a molecule with the VSEPR formula, but not the angles, will we need to know how to calculate for the angles?

[Snigdha Uppu 1G]

Yes we need to know the bond angles based on the molecular shape.

[Naji Sarsam 1F]

You do not need to do any mathematical calculations to determine angles. Rather you have to memorize the angles present in each molecular geometry, and that every time a bonding pair of electrons is replaced by a lone pair, those angles decrease.

Linear molecules have an angle of 180
Tetrahedral molecules have an angle of 109.5
Trigonal bipyramidal molecules have angles of 90, 120, 180
Octahedral molecules have angles of 90, 180

[Nohemi Garcia 1L]

There isn't a way to calculate bond angles (or at least in this course) because the exact angles are found experimentally. I think you will be fine if you just memorize the general bond angles given for each shape.

[Caitlin Ciardelli 3E]

From the VSEPR formula we can find approximations of bond angles by comparing to whether they will be greater or less than our ideal angles (90, 180, 109.5 etc.) The only way to find the exact values is by using the Schrodinger equation which has not been covered thus far! Hope this helps :)

[Maya Serota 3G]

We will only need to be able to make comparisons to the bond angles discussed in class and understand why bond angles might be smaller or larger due to electron repulsion.