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Lewis structures that are not symmetrical

Posted: Sat Nov 09, 2019 11:45 pm
by Jorja De Jesus 2C
If a lewis structure has atoms arranged around its central atom non-symmetrically then it is a polar atom right? What draws the line between symmetrical and not symmetrical? For example if there are 5 atoms around the central atom, the atoms could be arranged around it so that it can be either symmetrical (if it looks like an upright star) or not symmetrical (if it looks like a sideways star). How would you be able to tell if the molecule is polar or not?

Re: Lewis structures that are not symmetrical

Posted: Sun Nov 10, 2019 12:17 am
by 305416361
I could be fully wrong here so if I am please someone else correct me:
I believe that polarity has to do with the distribution/sharing of electrons, so regardless of which way the structure is "turned" when drawn, if the electrons are distributed equally then it is non polar, and if they are shared unevenly, then it is polar

Re: Lewis structures that are not symmetrical

Posted: Sun Nov 10, 2019 4:01 pm
by Anne Tsai 1F
I think polarity is determined by the difference in electronegativities between atoms in a molecule. However, symmetry does play a role with a molecule like CO2, which is nonpolar overall despite the charge differences between C and O because the oxygens pull on the carbon in the center equally and in opposite directions.

Re: Lewis structures that are not symmetrical

Posted: Sun Nov 10, 2019 4:51 pm
by Dan M -3E
I think for a single atom that has 5 electrons, it would still be considered nonpolar because the electrons move around the nucleus and end up being equally distributed, on average, around the because they move so fast around it.

Re: Lewis structures that are not symmetrical

Posted: Mon Nov 11, 2019 11:12 pm
by Shail Avasthi 2C
It depends on the molecule. When you arrange 5 identical atoms around a central atom (e.g. PF5), this molecule will be non-polar because of the shape of the molecule. You can also have a symmetrical molecule that is polar (e.g. CH2Cl2) due to dipole moments etc.. Symmetry is not a reliable way to determine polarity because there are many exceptions. The best way to tell if a molecule is polar or not is to look for dipole moments / lack thereof.