How to tell if a molecule is symmetrical - Polar Molecules Part 2 - Real Chemistry

In this video we continue our series on determining if a molecule is polar. In the first video in the series, we learned how to determine if a bond is polar. A molecule is polar if it contains a polar bond AND it is asymmetrical. In this video we turn to this second requirement.
We learn how to tell if a molecule is asymmetrical by looking for either one of two key features 1) A lone pair on the central atom OR 2) Different terminal atoms. If either are present, the molecule is asymmetrical. We discuss two exceptions to the lone pair rules (linear or square planar molecular geometries.) Lastly, we apply these rules to a series of examples to determine if the molecule are symmetrical or not.
How to Determine Molecular and Electron Geometry
• How to find electron a...
Polar Molecules Part 1
How to tell if a BOND is polar
• How to find electron a...
Polar Molecules Part 3
How to tell if a molecule is polar
• How to tell if a molec...
Polar Molecules Part 4
How to tell if organic molecules are polar
• How to tell if organic...
You also may want to know how to determine a molecules geometry before watching this video. Here is a helpful video on that:

[@williamperry5767]

BRO thank you so much man, I have no idea why people cannot make it as straightforward as this. Ridiculous, thank you.

[@jashangill2854]

thanks for explaining this properly, now I understand this.

[@jamie-lynngoulter2494]

I have been looking forever for an explanation that makes sense and you just cleared this up for me within the first minute thank you

[@PinK_2222]

thank you so much , I have been looking for way too long to find a good video that explains this :' )

[@user-ni9zu7by3t]

THANK YOU, finally found a video that explains it better than any other including my teacher.

[@andreamontiel2032]

Thank you very much sir this is helping me with my class. I am able to understand this unit much better👍🏽🙏🏽

[@scoobydoobydoo777]

Can someone help me to understand the last one XeF3H,is it symmetrical or asymmetrical?

[@biowolf3217]

fucking legend only person who isn't borning and can actually explain the topic

[@pkmkb0]

Heyy sir thanks a lottt for this video it helped me a lottt!!
U explained it very Cleary thx! ❤️

[@shortcakecake2702]

thank you so much!

[@zahrahalsaeed3175]

You’re amazing 😻

[@johnathann.77]

Thank you so much man my teacher can't explain this you're gonna save my exam tomorrow

[@alyssak859]

Thank you for doing the H2O one, I don't really understand why AX2E2 isn't symmetrical (I get the bent thing, but I still don't understand why that's not symmetrical - if you make a vertical cut, isn't that symmetrical?) So having a "rule" to follow helps a lot!!

[@RealChemistryVideos]

You are right that there is a plane of symmetry down the middle of AX2E2, this sort of symmetry isn't important here...but it does show why this discussion is always so confusing. Really we want to know if the vectors representing the polarity of each bond add to zero or not....of course to do this rigorously requires doing vector addition which is never really done in a general chemistry setting. Which really does make the rules the best way to go :)
If you watch my third video in this series it talks about qualitatively thinking through the vector addition which might help you see why AX2E2 isn't symmetrical in the way thats important, but it is complicated!

[@alyssak859]

@@RealChemistryVideos Thank you, I am working my way through your videos alongside my course. (On every topic that comes up!) You are the only reason I understand any of it! Lol

[@isabelsmith8072]

If you are working with organic molecules, could you count the molecules surrounding the atom as terminal atoms? for example for propanone, would it be asymmetrical because there are two CH3 molecules and one oxygen connected to the carbon, which are different terminal 'molecules'?

[@RealChemistryVideos]

Hi Isabel,
You can apply these same rules at every individual atom in a large molecule. If it has a single atom with different terminal atoms or lone pairs then the whole molecule will be asymmetrical. Typically there is some asymmetry in organic molecules. To decide if they are polar, you typically just need to see if it has a polar bond.

[@Fauna.AnimalKingdom]

Thank you so much🥺🕊

[@adolfocomparan5997]

Thanks so much for this.

[@atomgaming1413]

7:00 it has a lone pair and has different atoms so it meets both options to be asymmetrical atom why you consider it as a symmetrical atom -_-

[@whatdoesthisnamedo]

well 4 bonds and 2 sets of lone pairs means it's one of the exceptions. but yes it does have different terminal atoms so it is asymmetrical. i think it was a mistake in the powerpoint (or whatever he uses), he also said that it was asymmetrical

[@RealChemistryVideos]

Good summary Carl! That is correct...I circled that wrong word. It is asymmetrical because of the differing terminal atoms.

[@rowandas952]

ur so good taught what my teacher couldn't
in 20x time

[@jamesm.3829]

this helps so much!

[@yashaska2187]

Thank you bro

[@hahathree6482]

Is BH3 polar or no polar?

[@banelemabaso658]

Doesn't H2O have a bent shape instead of linear?

[@RealChemistryVideos]

Yes it does!

[@banelemabaso658]

But you said it is linear and that's why it is asymmetrical

[@hahathree6482]

Are all asymmetrical molecules polar?

[@Waseemmmm]

1:57 Methane has no lone pairs or different terminal atoms, I wish you talked about it

[@RealChemistryVideos]

That is correct. Because of this it is symmetrical

[@lawo2041]

i have a question

[@neeravshah743]

based on your video, ozone O3 would be asymmetrical and thereby polar, but ozone is really symmetrical and non-polar

[@RealChemistryVideos]

Ozone is asymmetrical, but it lacks polar bonds so its non-polar.

[@Peter-th5my]

you circled the wrong answer for the last practice question

[@RealChemistryVideos]

Doh! You are right, thanks for pointing this out.

[@LabibaBinteWali]

so ionic compounds can never be symmetrical?

[@RealChemistryVideos]

Hmmm this is kind of complicated. The way we write binary ionic compounds like (NaCl) would not have symmetry according to the rules we listed. And they are always ionic which is sort of like super polar.
However, ionic compounds form crystal lattices which have various types of symmetry but not the symmetry discussed here. So I think what you said is right haha.

[@mikasaackerman8682]

Thank you sir but I’ve got a question
What if the molecule is asymmetrical but has non polar bonds ??

[@RealChemistryVideos]

Hi Mikasa,
This video is just thinking about the symmetry. But you are right that to think about if a molecule is polar you have to consider bother symmetry and bond polarity. For the example you gave, you'd have a non-polar molecule because polar molecules must have BOTH a polar bond and asymmetry.
Here is a video which covers that topic in more depth: th-cam.com/video/28PrVC5TIBA/w-d-xo.html

[@mikasaackerman8682]

@@RealChemistryVideos thankyou sir !

[@mikasaackerman8682]

@@RealChemistryVideos thank you 🙏

[@sonicshoes9299]

@@RealChemistryVideos my chemistry teacher taught this flow chart where if there was no polar bonds we had to check symmetry. Then if it was not symmetrical, it was polar

[@RealChemistryVideos]

@@sonicshoes9299 Unfortunately that isn't correct. If a molecule has no polar bonds, it can't be a polar molecule.

[@Bea-jl9lt]

Why don't we learn geometries first?! I hate it when they say to "just look at it".

[@newsecretseed8333]

How is h2o asymmetrical lol

[@RealChemistryVideos]

This is one that can be tricky! Students often draw it H-O-H with a lone pair on top and bottom. This make its look linear and quite symmetrical. But actually it should be drawn in a bent fashion with both hydrogens pointing down. This makes it clear that the lone pairs (as suggested in the rules) break the symmetry.

[@ciobi202]

Pov: you are from Romania and the only good videos are in english:)