Polar Molecule

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Nicole Garrido 2I
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Joined: Fri Sep 28, 2018 12:18 am

Polar Molecule

Postby Nicole Garrido 2I » Mon Nov 26, 2018 5:59 pm

Is a polar molecule any molecule with charges? If there is a net charge of 0 is it non polar (ex. central atom has +2 and two bonded atoms have -1 each)?

Posts: 36
Joined: Fri Sep 28, 2018 12:25 am

Re: Polar Molecule

Postby 405161024 » Mon Nov 26, 2018 6:05 pm

not necessarily, because a water molecule is polar even though it is neutral; I think it depends on the electronegativity of the atoms in the molecule

Andonios Karas 4H
Posts: 30
Joined: Fri Sep 28, 2018 12:27 am

Re: Polar Molecule

Postby Andonios Karas 4H » Mon Nov 26, 2018 6:10 pm

Whether a molecule is nonpolar or polar depends on the net dipole moment, not the formal charges.
A dipole can be determined by looking at the electronegativity of two atoms that are bonded. The more electronegative atom will pull more on the electrons, leading to a dipole.
After the 3D structure is determined, dipoles can be drawn as an arrows between atoms with it pointing towards the more electron negative atom. If the arrows do not cancel (net dipole =/= 0), the molecule is nonpolar. If the arrows do cancel (net dipole moment = 0), the molecule is polar.
Here is a picture showing why CO2 is nonpolar and H2O is polar.

Ethan Nishikawa 4D
Posts: 36
Joined: Fri Sep 28, 2018 12:16 am

Re: Polar Molecule

Postby Ethan Nishikawa 4D » Mon Nov 26, 2018 6:22 pm

The formal charge of a molecule could be zero but still be polar. Typically, a molecule is only non-polar if there is only one type of element surrounding an atom. If there are two or more types of elements surrounding an element, the molecule will probably be polar.

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