Molecular Shape Patterns

[Sara Sadrolsadat 1G]

When it comes to determining molecular shapes of formulas, must we memorize the conditions of each shape, or are there any patterns or trends in molecular shapes that we can look to to help us determine them, without necessarily having to memorize each shape independently?

[Isabelle Fontanilla 1I]

I think we pretty much have to memorize the conditions for each shape. Making use of the VSEPR notation helps a lot, but it still requires that you know the conditions of each shape. As for trends, I am not aware of any existing.

[Bruce Chen 2H]

Unfortunately, there doesn't seem to be a pattern. I think we just have to memorize it at this point.

[Yvonne Du]

I think in the lecture we went over some notations about the VSEPR model:
A=central atom
X=bonded atom
E=lone pair

For example, AX3 is trigonal planar, AX2E2 is bend, AX4 is tetrahedral, AX4E is trigonal bipyramidal, and AX4E2 is Square planer.

I think remembering these can save you some time.

Hope this helps.

[Sapna Ramappa 1J]

Unfortunately, I think we just have to purely memorize the different shapes and the names of them. However, if you're a visual learner, there are a bunch of helpful charts online that helped me! Here's one: https://chemstuff.co.uk/academic-work/a ... molecules/

[JiangJC Dis2K]

I think we basically just need to memorize all of them, though some of the angles could probably be determined by visualizing. There are a lot of shapes, but what helped me was to make an organized table of the formulas using the VSEPR notation of A, X, and E and then the shape, bond angle(s), and hybridization (once we go over that). If you study the table and formulas, it does kind of become a patter because, say, if the test gave you CH5, you would be able to see that as AB5 and label it as trigonal bipyramidal.