How to tell polar or non polar from lewis structure?

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

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Junwei Sun 4I
Posts: 125
Joined: Wed Oct 02, 2019 12:16 am

How to tell polar or non polar from lewis structure?

Postby Junwei Sun 4I » Fri Nov 15, 2019 4:13 pm

Could someone please clarify how we can tell if a molecule is polar or non-polar from looking at its lewis structure? What are some factors in a lewis structure that will make a molecule polar?

chemboi
Posts: 101
Joined: Sat Jul 20, 2019 12:16 am

Re: How to tell polar or non polar from lewis structure?

Postby chemboi » Fri Nov 15, 2019 4:27 pm

Presence of asymmetric lone pairs, and asymmetric distribution of atoms with electronegativity differences are indicators of polarity

Zoya Mulji 1K
Posts: 105
Joined: Thu Jul 11, 2019 12:15 am

Re: How to tell polar or non polar from lewis structure?

Postby Zoya Mulji 1K » Fri Nov 15, 2019 5:17 pm

If you have the lewis structure, you can draw your dipole arrows considering electronegativity and if the arrows don't balance out then the molecule will be polar.

Alan Wu
Posts: 61
Joined: Sat Sep 14, 2019 12:16 am

Re: How to tell polar or non polar from lewis structure?

Postby Alan Wu » Fri Nov 15, 2019 6:22 pm

If the dipole moments in a lewis structure cancel out, then the molecule will be nonpolar.
If there are lone pairs of e-, the molecule is almost always polar.
If the dipole moments don't cancel out and point in one general direction, then the molecule is polar.

Aayush Patel 3B
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Joined: Thu Jul 25, 2019 12:17 am

Re: How to tell polar or non polar from lewis structure?

Postby Aayush Patel 3B » Fri Nov 15, 2019 7:25 pm

If a hydrogen bond is present anywhere throughout the molecule and the dipoles do not cancel due to symmetry, than that respective molecule will be polar.

Debora Fernandez Clemente_ 4H
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Joined: Wed Sep 18, 2019 12:21 am

Re: How to tell polar or non polar from lewis structure?

Postby Debora Fernandez Clemente_ 4H » Fri Nov 15, 2019 10:17 pm

Are going to have to determine on whether a molecule is polar or not?

Destiny_Ryales_3J
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Joined: Fri Sep 28, 2018 12:28 am

Re: How to tell polar or non polar from lewis structure?

Postby Destiny_Ryales_3J » Fri Nov 15, 2019 10:22 pm

Is this supposed to be on next week’s test?

AGulati_4A
Posts: 74
Joined: Sat Sep 07, 2019 12:19 am

Re: How to tell polar or non polar from lewis structure?

Postby AGulati_4A » Fri Nov 15, 2019 10:23 pm

A polar structure has non-cancelling electronegativity vectors while a non-polar structure has cancelling ones.

Kaitlyn Jang 1F
Posts: 45
Joined: Sat Aug 17, 2019 12:16 am

Re: How to tell polar or non polar from lewis structure?

Postby Kaitlyn Jang 1F » Sat Nov 16, 2019 1:27 am

Check to see if the dipoles cancel out in molecules. It helps to draw out arrows to signify the dipoles of each atom to visually see if they cancel out or not to create a polar or nonpolar molecule.

Rebekah Alfred 1J
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Re: How to tell polar or non polar from lewis structure?

Postby Rebekah Alfred 1J » Sat Nov 16, 2019 9:59 am

Destiny_Ryales_3J wrote:Is this supposed to be on next week’s test?

My TA said that we should know about polar and non-polar molecules for Test 2.


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