lone pairs -polar molecule

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Bethany Yang 2E
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lone pairs -polar molecule

Postby Bethany Yang 2E » Sat Nov 28, 2020 11:00 am

If any of the elements within the atom have a lone pair, could you automatically assume that it is a polar molecule?

Yu Jin Kwon 3L
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Re: lone pairs -polar molecule

Postby Yu Jin Kwon 3L » Sat Nov 28, 2020 11:20 am

Hi Bethany! I would say no because if you have a diatomic molecule such as Br2, in which each Br atom has 3 lone pairs, but it is still a nonpolar molecule. Rather than just looking for lone pairs, I would say to look at the difference in electronegativity to determine polarity :)
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Ria Nawathe 1C
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Re: lone pairs -polar molecule

Postby Ria Nawathe 1C » Sat Nov 28, 2020 11:21 am

I don’t think you can assume that any molecule with a central atom that has lone pairs is polar. For example, XeF2 is non polar, and it has 3 lone pairs on the central atom. The lone pairs are arranged at 120 degrees to each other and the F-Xe-F bond angle is 180 degrees, so there is a 0 net dipole moment due to this symmetry.

105618850
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Re: lone pairs -polar molecule

Postby 105618850 » Sun Nov 29, 2020 3:14 am

I wouldn't say that would be the case for every molecule. For example, for compounds like H2, Cl2, etc. are all considered non polar.

Sera Aintablian 2E
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Re: lone pairs -polar molecule

Postby Sera Aintablian 2E » Mon Nov 30, 2020 1:19 am

No, some molecules, such as diatomic molecules, are nonpolar.

Madeline Ogden 3B
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Re: lone pairs -polar molecule

Postby Madeline Ogden 3B » Tue Dec 01, 2020 12:29 pm

You cannot assume this because of the fact that if the molecule is symmetrical the charges might cancel out despite the atoms having lone pairs.

Sabrina Galvan 3J
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Re: lone pairs -polar molecule

Postby Sabrina Galvan 3J » Wed Dec 02, 2020 2:17 pm

In some molecules, the presence of a lone pair causes the molecule to lose its symmetry, therefore its dipoles would not cancel out causing it to be a polar molecule. But as many have mentioned, lone pairs are not determinedly a factor of polar molecules. It is best to look at how the lone pairs are a factor in molecule shape to determine its polarity.

David Liu 1E
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Re: lone pairs -polar molecule

Postby David Liu 1E » Sun Dec 06, 2020 2:38 am

I would definitely first look at the bond angles, because not every molecule with lone pairs would be polar as they could be evenly spaced from each other

Jeremy Wei 2C
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Re: lone pairs -polar molecule

Postby Jeremy Wei 2C » Sun Dec 06, 2020 9:19 pm

Hi, I wouldn't assume that if a molecule has lone pairs it would be polar, since for example diatomic molecules do have lone pairs but are nonpolar because the dipole moments cancel out.

alexandralopez 3F
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Re: lone pairs -polar molecule

Postby alexandralopez 3F » Sun Dec 06, 2020 9:23 pm

i dont think that would be accurate. I would say just look at the geometry of the molecule

Algernon Jackson 2l
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Re: lone pairs -polar molecule

Postby Algernon Jackson 2l » Sun Dec 06, 2020 9:23 pm

No because there is still a possibility that they might be non-polar.


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