Differences in Bond Angles with Same VSEPR Formula?

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Kushaal Madadi 2F
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Differences in Bond Angles with Same VSEPR Formula?

Postby Kushaal Madadi 2F » Mon Nov 30, 2020 8:34 pm

O3 and NO2- both have the same VSEPR formula. Why then, are the bond angles for 03 116.8 degrees and the bond angles for NO2- 116 degrees? Does this have to with central/surrounding atom size or electronegativities?

KatarinaReid_3H
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Re: Differences in Bond Angles with Same VSEPR Formula?

Postby KatarinaReid_3H » Mon Nov 30, 2020 10:00 pm

The bond angle decreases as the central atom's size increases. Thus, since Nitrogen is slightly larger than Oxygen, the NO2- should have a slightly smaller bond angle. Also, if the electronegativity of the central atom decreases, then the bond angle decreases.

Faith St Amant 3D
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Re: Differences in Bond Angles with Same VSEPR Formula?

Postby Faith St Amant 3D » Mon Nov 30, 2020 11:07 pm

Exactly^! Dr. Lavelle has mentioned, though, that we will not be expected to know these exact angles--we just need to know which normal bond angle (90, 109.5, 120, etc.) the angle will be slightly less than due to repulsion from lone pairs.

Inderpal Singh 2L
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Re: Differences in Bond Angles with Same VSEPR Formula?

Postby Inderpal Singh 2L » Mon Nov 30, 2020 11:32 pm

I believe if the electronegativity of the central atom decreases, so will the bond angle.

Emerald Wong 1B
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Re: Differences in Bond Angles with Same VSEPR Formula?

Postby Emerald Wong 1B » Tue Dec 01, 2020 9:53 am

The bond angle varies with multiple factors. For this specific example, you can look at electronegativity. The bond angle will decrease as electronegativity decreases. You can also look at the size, since those with more electrons will have more repulsion and create a smaller bond angle. We don't need to know specific numbers; just knowing an approximation or knowing it's less than some number should be enough.


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