Bond Angles

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

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Tessa Lawler 1A
Posts: 57
Joined: Fri Sep 28, 2018 12:18 am

Bond Angles

Postby Tessa Lawler 1A » Sat Dec 08, 2018 10:10 pm

Hey guys!
Quick question on bond angles in molecular shapes.
When we're asked about the bond angles in a molecule, are we providing only the angle between the atoms branched off the center, or also the angles between those atoms and the central atom?
To clarify:
If you have AX2E, a bent molecule, is 120 degrees the angle between the two x atoms, or between the x and the a atom as well? Same question for AX2E2 - is 109.5 the angle between only the two X's, or between an x and the a as well?
Thanks!

Christopher Wendland 4F
Posts: 30
Joined: Fri Sep 28, 2018 12:29 am

Re: Bond Angles

Postby Christopher Wendland 4F » Sat Dec 08, 2018 10:14 pm

The A is the central atom and is the origin point, it is just the pivot point and there cant be an angle between it and the atoms attached to it because it is just a line with a point on each end. There is an angle between the two X's because they are both attached to the central atom and form a wedge with 3 points always going from one of the X's to the A and then back to the second X.

Tessa Lawler 1A
Posts: 57
Joined: Fri Sep 28, 2018 12:18 am

Re: Bond Angles

Postby Tessa Lawler 1A » Sat Dec 08, 2018 10:56 pm

That makes sense. Thanks for your help!

danicatran4
Posts: 35
Joined: Fri Sep 28, 2018 12:17 am

Re: Bond Angles

Postby danicatran4 » Sat Dec 08, 2018 11:37 pm

If a molecule is bent, wouldn't the angle be slightly less than 120 or 109.5 degrees since there would be a stronger repulsion by the lone pair of electrons?


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