AsO43-

(Polar molecules, Non-polar molecules, etc.)

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Agustina Santa Cruz 2F
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Joined: Wed Sep 30, 2020 10:01 pm

AsO43-

Postby Agustina Santa Cruz 2F » Sun Nov 29, 2020 9:48 pm

How is AsO43- a nonpolar molecule if it has a charge?

Izamary Marquez 2H
Posts: 94
Joined: Wed Sep 30, 2020 9:44 pm

Re: AsO43-

Postby Izamary Marquez 2H » Sun Nov 29, 2020 9:51 pm

It helped me to draw out the dipole arrows! You will see that they point in opposite directions, which cancel out the distribution!

dana hu 1B
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Re: AsO43-

Postby dana hu 1B » Sun Nov 29, 2020 9:51 pm

because all 4 of the oxygen surrounding As is canceling out each individual vectors, therefore it is nonpolar.

Molly Posta 1H
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Re: AsO43-

Postby Molly Posta 1H » Sun Nov 29, 2020 9:52 pm

I think this is because even though there is a negative charge, there is no net dipole, so the molecule isn't polar. Dipole moment is a measure of polarity of a molecule, so that's what I look at when determining whether a molecule is polar, rather than looking at the overall charge for that molecule.

Tam Nguyen 2B
Posts: 74
Joined: Wed Sep 30, 2020 9:43 pm

Re: AsO43-

Postby Tam Nguyen 2B » Sun Nov 29, 2020 9:56 pm

The -3 is to indicate the additional electrons and the formal charge of the overall molecule. The most stable structure of AsO4 3- is in the form of a tetrahedral. Although the bonds are polar, all the oxygens are equidistant from each other and have resonance, meaning that the compound itself is nonpolar.

Alex Benson
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Re: AsO43-

Postby Alex Benson » Sun Nov 29, 2020 9:57 pm

It is a nonpolar molecule because it has charges in opposing directions that cancel each other out!

Mackenzie Van Val 3E
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Re: AsO43-

Postby Mackenzie Van Val 3E » Sun Nov 29, 2020 9:57 pm

AsO43- has a symmetric distribution of O around the central As, and all four atoms surrounding As are the same and thus will have the same electronegativity (and the same dipole moment with As). Therefore, the dipole moments between the As and each O will cancel out. Drawing the dipole arrows on the Lewis structure can be very helpful for seeing this. Hope this helps!

Alan Huang 1E
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Re: AsO43-

Postby Alan Huang 1E » Sun Nov 29, 2020 9:59 pm

To find polarity of a molecule, you should check only electronegativity.

In the case of AsO4 3-, the molecule is nonpolar when you look at the predominant resonance structure. The molecule is tetrahedral and has a dipole moment because of the difference in electronegativities between arsenic and oxygen, but it cancels out.

Aria Movassaghi 1A
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Joined: Wed Sep 30, 2020 9:40 pm

Re: AsO43-

Postby Aria Movassaghi 1A » Sun Nov 29, 2020 10:25 pm

The charges cancel out so there is no net dipole moment.

DominicMalilay 1F
Posts: 107
Joined: Wed Sep 30, 2020 9:36 pm

Re: AsO43-

Postby DominicMalilay 1F » Sun Nov 29, 2020 10:49 pm

Even though it is an ion, the charges cancel so it is nonpolar.


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