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Polar v. Non Polar

Posted: Wed Nov 14, 2018 4:33 pm
by duenezjuleny1D
How do you identify whether or not something is polar or non polar? what does it depend on?

Re: Polar v. Non Polar

Posted: Wed Nov 14, 2018 4:46 pm
by Samantha Man 1L
You have to look at the electronegativities. If the atoms have about the same electronegativity, then the molecule is non-polar and if the atoms have different electronegativities, then the molecule is polar because electrons are being unequally shared in the molecule.

Re: Polar v. Non Polar

Posted: Wed Nov 14, 2018 4:52 pm
by Layal Suboh 1I
Hi!

You can determine if some molecules are polar based on the difference in electronegativity of the bond (ie if the difference in electronegativity is between 0 and 0.4, the bond is non polar. If the difference is between 0.5 and 1.4, the bond is polar) . For example, N2 is non-polar because the difference in electronegativity is 0. Also, it is important to look at the dipole moments in order to check if a molecule is polar/non polar. For example, CO2 looks like a polar molecule because the bonds are polar based on the difference in electronegativity, but overall, it is a non polar molecule because the dipole moments cancel out. There is a polar bond between the C and O, but the two dipole moments cancel out, making CO2 an overall non polar molecule.

Hope this helps!

Re: Polar v. Non Polar

Posted: Fri Nov 16, 2018 1:58 pm
by Nikki Bych 1I
Another way to think of it is molecules like BF3 and CH4 are non polar because they are all being pulled equally in each directly (dipoles cancel) but in molecules such as H20, there is an overall dipole so it is polar.

Re: Polar v. Non Polar

Posted: Fri Nov 16, 2018 5:12 pm
by Cade Okohira 4K
I was wondering does polarity always have to do with the symmetry of the molecule or are there exceptions?

Re: Polar v. Non Polar

Posted: Fri Nov 16, 2018 5:19 pm
by Lucy Agnew 3E
Cade Okohira 1I wrote:I was wondering does polarity always have to do with the symmetry of the molecule or are there exceptions?


I think symmetry plays a role in guessing whether the molecule is polar or not, but you also have to consider the electronegativities of the atom as this is really important. There are probably exceptions but I don't know them off the top of my head sorry!

Re: Polar v. Non Polar

Posted: Sun Nov 18, 2018 5:19 pm
by Arshia Ramesh 1G
Look at the electronegativity when you're trying to determine if something is polar/nonpolar

Re: Polar v. Non Polar

Posted: Fri Nov 23, 2018 12:13 am
by Henry Dudley 1G
What are some common exceptions when trying to determine polar or non polar based on symmetry?