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Qube

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## Homework Statement

Number 17:

http://i.minus.com/jbqSc694thPeBA.jpg [Broken]

## Homework Equations

I'm not even sure where to start.

## The Attempt at a Solution

I know that tetrahedral shapes are non-polar if all of the attached elements are the same (e.g. CH4 or CCl4).

I know all the answer choices are factually correct. I'm just unsure of how any of them would justify that all the others are tetrahedral.

Well I know that the answer is 3, but why? This is the best explanation I've been able to come up with; that if CH3CL were square planar and had two lone pairs, one on top, and one below, the tetrahedron, the resultant net dipoles (circled in the second diagram I drew below) would cancel out. The first diagram I drew is just of the regular tetrahedron CH3Cl. We know that CH3Cl has to be polar but if it were square planar it wouldn't be polar anymore and this would justify the fact that all the carbon compounds in the answer choices are tetrahedral.

http://i1.minus.com/jBchuhvMGOTFh_e.jpg [Broken]

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