Polar VS Nonpolar shapes

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

Moderators: Chem_Mod, Chem_Admin

sylvie_1D
Posts: 31
Joined: Fri Apr 06, 2018 11:04 am

Polar VS Nonpolar shapes

Postby sylvie_1D » Sun May 27, 2018 11:39 pm

Hi, so for non polar molecules I understand that there must be dipole forces that cancel each other out, though what exactly does this mean and how do they "cancel". Do the dipole moments have to be equal in strength or do there simply have to be "dipole moments".

Garrett Dahn 1I
Posts: 28
Joined: Fri Apr 06, 2018 11:02 am
Been upvoted: 1 time

Re: Polar VS Nonpolar shapes

Postby Garrett Dahn 1I » Sun May 27, 2018 11:52 pm

Sylvie--

The dipole moments of non polar molecules will cancel out insofar as the individual dipole vectors will literally cancel out: two perfectly horizontal dipole vectors going in opposite directions ( --> <--) would, for example, cancel out. The vectors cancel the way a vector in physics might cancel -- a force going one way can offset a force going in the exact opposite way. For this reason, the dipole moments should need to be of equal strength to cancel each other out in the way that gravitational force and normal force cancel out on earth to keep us on the ground.

Hope this can help!

Ignacio Ramirez 1J
Posts: 31
Joined: Tue Nov 14, 2017 3:02 am

Re: Polar VS Nonpolar shapes

Postby Ignacio Ramirez 1J » Tue May 29, 2018 6:01 pm

If a molecule is completely symmetric, then the dipole moment vectors on each molecule will cancel each other out, making the molecule nonpolar. A molecule can only be polar if the structure of that molecule is not symmetric. Dipole moments need to have equal strength.

Salena Chowdri 1I
Posts: 66
Joined: Fri Apr 06, 2018 11:02 am

Re: Polar VS Nonpolar shapes

Postby Salena Chowdri 1I » Wed Jun 06, 2018 3:54 pm

The dipole moments have to be equal in strength, so 2 of the same bonds can cancel each other out. "Cancel" here means opposing vectors. However, when you're considering whether a compound is polar or nonpolar always think of the structure in 3D.

Daniel Cho Section 1H
Posts: 29
Joined: Fri Jun 23, 2017 11:40 am

Re: Polar VS Nonpolar shapes

Postby Daniel Cho Section 1H » Thu Jun 07, 2018 11:01 am

In addition, the polarity is focused on the electronegativity negativity. So compounds like F2 is nonpolar because their electronegativity difference is very small. It also depends on the molecular shape but you more so have to draw it out to see if any of the dipole moments cancel out.

I hope this helps. Please correct me if I am wrong in certain places.


Return to “Determining Molecular Shape (VSEPR)”

Who is online

Users browsing this forum: No registered users and 2 guests