Polar v. Non Polar

[duenezjuleny1D]

How do you identify whether or not something is polar or non polar? what does it depend on?

[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.

[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!

[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.

[Cade Okohira 4K]

I was wondering does polarity always have to do with the symmetry of the molecule or are there exceptions?

[Lucy Agnew 3E]

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!

[Arshia Ramesh 1G]

Look at the electronegativity when you're trying to determine if something is polar/nonpolar

[Henry Dudley 1G]

What are some common exceptions when trying to determine polar or non polar based on symmetry?