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Vectors for Dipole Moments

Posted: Fri Nov 16, 2018 9:26 pm
by Nathan Mariano 2G
When drawing the Lewis structure of a compound, how do we determine the vectors for each atom? From the vectors, how do we deduce that a molecule is polar or nonpolar?

Re: Vectors for Dipole Moments

Posted: Fri Nov 16, 2018 9:35 pm
by JT Wechsler 2B
When a molecule has two elements that are bonded together with an electronegativity difference, the electrons will tend to "hang around" the atom with the higher electronegativity. This means that the area around that atom will be slightly more negative and will thus create a dipole. In this case, a vector would be drawn on the Lewis structure (or a delta +/-) depending on the atom you are looking at. Then, to deduce the polarity of a molecule, you will want to look at the geometric shape of the molecule as well as the other neighboring atoms. If a molecule has a nonpolar geometric shape and all of the atoms surrounding the central atom are the same element, then the molecule will be nonpolar because the dipoles cancel each other out. However, if one of the bonded atoms differ or if the molecular shape is not nonpolar, then the molecule will be polar.