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

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Sarah Blake-2I
Posts: 153
Joined: Fri Aug 30, 2019 12:16 am


Postby Sarah Blake-2I » Sat Nov 16, 2019 3:32 pm

Can someone explain how you can determine what the shape of a molecule is if it has lone pairs. For instance, what makes something seesaw shaped? I am just a bit confused.

Megan Ngai- 3B
Posts: 50
Joined: Fri Aug 09, 2019 12:17 am


Postby Megan Ngai- 3B » Sat Nov 16, 2019 3:43 pm

I just follow this chart!
Screen Shot 2019-11-16 at 3.43.28 PM.png

Jada Brown 2H
Posts: 100
Joined: Sat Aug 17, 2019 12:15 am


Postby Jada Brown 2H » Sat Nov 16, 2019 3:45 pm

honestly its mostly just memorization of the different shapes, taking into consideration the number of electron dense areas, and whether or not those areas involve lone pairs or not.

Posts: 50
Joined: Fri Aug 30, 2019 12:18 am


Postby AnnikaMittelhauser4E » Sat Nov 16, 2019 4:27 pm

The chart is great but to understand it you could think of a seesaw molecule like SF4 like this:
1. SF4 has 5 regions of electron density because the lone pair is kinda like another S-F bond. So, I think of trigonal bipyramidal as the "template" shape because that's what's formed by central molecules with 5 bonds.
3. Except, one of those 5 "bonds" is actually a lone pair. That makes it invisible when actually drawing or naming the structure (like one bond of the trigonal bipyramidal shape disappeared but nothing else changed). So, seesaw is like modified trigonal bipyramidal, the lone pair contributes to the shape but is ignored in naming.

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