Determining Shape

[chrisavalos-2L]

I was wondering if there was an easy short way in determining the shape of a molecule based on its molecular formula without drawing the Lewis structure first? Or is the Lewis structure necessary for determining the shape?

[Tony Ong 3K]

you want to draw out the lewis structure always to determine what the Steric Number is for the central atom...then you can determine shape from there.
Don't cheat your way with shortcuts!!!! It'll be your ultimate downfall!

oh and steric number means bonded pairs of electrons (double bond counts as one) AND lone pairs of electrons

have a good thanksgiving :)

[Tony Ong 3K]

you want to draw out the lewis structure always to determine what the Steric Number is for the central atom...then you can determine shape from there.
Don't cheat your way with shortcuts!!!! It'll be your ultimate downfall!

oh and steric number means bonded pairs of electrons (double bond counts as one) AND lone pairs of electrons

have a good thanksgiving :)

[MinaChoi_3H]

You will always need to draw the lewis structure because a compound can have numerous structures drawn and you need to find the one with the lowest energy to be able to find the correct shape as well as the reason mentioned above.

[Karla_Ocampo 4E]

I think its best to always draw the lewis structure so you can get the most accurate answer. This way you will be able to find the shape, lone pairs, etc..

[Hanlin Zhu 4G]

It is hard to know the number of bonding pairs and lone pairs just by looking at the chemical formula. I think to be safe we have to draw the lewis structure.

[Ruiting Jia 4D]

I think besides just drawing the Lewis structure, what would also help is sketching or imagining the Lewis structure in 3d. The Lewis structure presents you with a very 2d linear version of what the model actually looks like.

[Madeline Motamedi 4I]

It's good to get in the habit of drawing the lewis structure and as you do them more and more it'll be easier and you'll become faster at drawing them.

[Nick Bazett 1F]

My TA said we can either memorize every shape, or use your intuition. She also said to draw them out.

[Nicole Jakiel 4F]

For now I would really just draw the Lewis Structures every time- eventually you may begin to pick up on certain patterns but as of right now drawing the Lewis Structure first is the best way to go!

[Estelle Jung]

In order to determine molecular shape, you should be able to find the steric number, which is the number of atoms and lone pairs bonded to the central atom.