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How to tell polar or non polar from lewis structure?

Posted: Fri Nov 15, 2019 4:13 pm
by Junwei Sun 4I
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?

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

Posted: Fri Nov 15, 2019 4:27 pm
by chemboi
Presence of asymmetric lone pairs, and asymmetric distribution of atoms with electronegativity differences are indicators of polarity

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

Posted: Fri Nov 15, 2019 5:17 pm
by Zoya Mulji 1K
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.

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

Posted: Fri Nov 15, 2019 6:22 pm
by Alan Wu
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.

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

Posted: Fri Nov 15, 2019 7:25 pm
by Aayush Patel 3B
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.

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

Posted: Fri Nov 15, 2019 10:17 pm
by Debora Fernandez Clemente_ 4H
Are going to have to determine on whether a molecule is polar or not?

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

Posted: Fri Nov 15, 2019 10:22 pm
by Destiny_Ryales_3J
Is this supposed to be on next week’s test?

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

Posted: Fri Nov 15, 2019 10:23 pm
by AGulati_4A
A polar structure has non-cancelling electronegativity vectors while a non-polar structure has cancelling ones.

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

Posted: Sat Nov 16, 2019 1:27 am
by Kaitlyn Jang 1F
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.

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

Posted: Sat Nov 16, 2019 9:59 am
by Rebekah Alfred 1J
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.