Shapes of Molecules | A level Chemistry

Shapes of Molecules.
A level Chemistry.
Explanation of VSEPR Theory and worked examples for working out the shapes of molecules.

[@PatelHarnisha-g9j]

Who hates bonding in chemistry 😢

[@chemistrytutor]

Hopefully this video has helped a bit! I've got some others about Polarity and intermolecular forces if that's any help?

[@areefsajid5726]

Us

[@nushiw4781]

Hi, thanks so much for this video, honestly THANK YOU it is a GODSEND! I really appreciate how you break down the topic and explain the concepts with clarity. Please continue making videos, your style of explaining is so easy to follow! 👏👏

[@IbrahimKhan-ft4bp]

I never comment on youtube videos but this is by far one of the most useful videos I've watched for chemistry. Thanks so much!

[@saimxx2396]

Hi can you make A2 videos pls! Your videos are so helpful for me especially because I can’t afford tuition. I just want to say thank you so much and I’m grateful for your videos.

[@nabilamhait5570]

Thank you so much, this was the best explanation I came across. I will share it with other students.

[@oliviah-v4p]

Only video I have found that explains this so coherently, thank you so much!

[@chemistrytutor]

@@oliviah-v4p that's lovely to hear! It's really great that you found it useful 😃

[@_User__name802]

I recently came across your channel and honestly, this is one of the best explanations I’ve ever seen. It’s so helpful. Thank you so much!

[@chemistrytutor]

That's lovely thank you 😊

[@Sara-ce7ey]

I can't thank you enough for your amazing videos. You saved me in As level. I would really appreciate it if you could please do A2 videos soon. I would really feel lost without them. When are you going to make amazing videos for A2?

[@ImmsNetto-iw4gy]

Very well explained and simple to understand.. .thank you very much for this amazing video,it marks the end of my struggle with VSEPR THEORY. ✌🏽🤝🏽

[@chemistrytutor]

That's lovely to hear! I'm really glad it's useful ☺️

[@orphicprince]

The way you explain everything is really pleasing! All of my confusions are now gone, especially the triangle shapes and the angles ಥ⁠‿⁠ಥ

[@chemistrytutor]

I'm really pleased that you're finding them useful!

[@orphicprince]

@@chemistrytutor do you where I can find topical questions with explained answers?

[@chemistrytutor]

@@orphicprince I've a number of question walkthrough videos with links in the description. E.g. kzbin.info/www/bejne/Y5jYeXiCZpikd5o

[@pallavisrikanth9748]

oh my goodness this is just brilliant, thank you SO much!!! will be watching all your other videos as well!

[@MK-sh7ol]

Great video, thanks sir. Just a quick question though. At 23:06 you said that the PF4- would have an angle of 117.5 however in my revision guide it says that the angles in the seesaw shape are 87 degrees (which is pretty much what you said) and 102 degrees..which is way less than 117.5!

[@chemistrytutor]

Thank you! You are correct. The bond angle in that example is actually 102. However, from all of the examples that I've seen for the different exam boards, all you need to remember is that the bond angle is reduced because of the lone pair. And since the reduction is typically by 2.5 then that's what I went for here. So... not always 100% true to real life, but will get you the mark in an exam 😀

[@MK-sh7ol]

@@chemistrytutor got it, thank you!

[@sitihajijah0502]

Hello, OMG THANK YOU SO MUCH FOR HELPING ME UNDERSTAND HOW TO DRAW THE BONDING STRUCTURE, I HAVE WATCH MULTIPLE VIDEO ON YT AND ONLY YOURS HELPS 😭😭❤️❤️

[@chemistrytutor]

That's lovely to hear! I'm really pleased you've found it useful. Well done for sticking at it 👏

[@Goingstrong2]

Amazing video... thank you for all your hard work in making our lessons much easier.. God's Blessings 😊

[@chemistrytutor]

Thank you for your kind words 😊 It's lovely to know the videos are helpful!

[@ke8980]

Another great video! Quick question, when drawing a trigonal pyramid, does the lone pair have to go between an electron bonding pair on the same plane as the paper and the bonding pair going in? Or could it go between any arrangement of the bonding electron pairs as it would still -2.5 degrees from the angle anywhere? Thank you from Katie

[@ke8980]

I think I have worked out my own question: that the lone pair is always positioned where a line connected atom would have been connected e.g on the same plane as the paper

[@chemistrytutor]

@@ke8980 yes that's correct! 😀 Thanks for watching!

[@doreenaddo1728]

Any more Alevel vids coming soon?

[@chemistrytutor]

Hi, yes definitely. Been taking a break, but more on the way

[@JO06]

this guys the goat man

[@chemistrytutor]

🤜🤛

[@smirkface7199]

how do you know what bond requires a wedge to be drawn or a broken line/ how do you know what molecule u are supposed to draw it for?

[@chemistrytutor]

For the tetrahedral, trigonal bipyramidal and pyramidal, you need one wedge and one dashed. They're usually drawn next to each other, but it doesn't matter which sections of the molecule goes on that bond. Octahedral needs 2 of each

[@smirkface7199]

@@chemistrytutor ok thank you so much!

[@anislittletvshow]

Hi, I was wondering if you could explain how to do this method with KrF2, because it doesn't seem to work. Or do you just have to draw out a dot-and-cross diagram and figure it out from there?

[@chemistrytutor]

Kr Valence electrons = 8 Bonded to 2 F = 2 No charge = 0 Total electrons = 10 Electron pairs = 5 Therefore trigonal bipyramidal starting point. Only 2 Kr-F bonds therefor 3 lone pairs. These lone pairs will make up the triangle in the equatorial positions. The bonds will be the axial positions and so the shape will be linear

[@fromjessica3009]

Hi Sir, I tried using this method for SO2 but I don't think it worked because I ended up getting 2 lone pairs but SO2 actually has 1 lone pair. Is SO2 an exception?

[@chemistrytutor]

Great question. Yes SO2 is an exception. It's because the oxygen needs an extra 2e so the bonds are both double bonds. Look our for this when you've got oxygen but not as the central atom. Not a common exam question luckily. You can solve this one with the help of the classic dot and cross diagram

[@vanshikabhatia7020]

have you done a video on polarisation/electronegativity?

[@chemistrytutor]

Hi, I know this is a slow response... but yes! There is also one about electronegativity too if needed kzbin.info/www/bejne/bmKnd42Hial3aMk

[@rachaelkenyon4712]

such a helpful video! When naming the molecules is the name defined by the amount of charge clouds? Eg 4 charge clouds-> tetrahedral?

[@chemistrytutor]

I'm glad it's useful! The number determines the shape, yes. But you don't include the lone pairs in the name of the shape. So water has 2 lone pairs and 2 bonding pairs. Its the 2 bonding pairs, that are in a V-shape, but the lone pairs caused the v-shape

[@PatelHarnisha-g9j]

I got a chemistry AS exam on Friday ,any tips or advice, and how to avoid making silly mistakes

[@chemistrytutor]

One of the most useful tips is to do with how you check what you've done. Once you've finished a question or finished the whole paper... Read your answer and *then* check the question. Doing it in that order means your thoughts don't follow the same paths each time, and you're more likely to spot if you've made a silly mistake, or assumption about the question. Good luck for the exam!

[@anishasameen2076]

4 years later and this video is still extremely helpful, thanks.

[@chemistrytutor]

Glad it helped! 😃

[@joyam8489]

Hi, first I would like to thank you for making this wonderful video. I have 2 particular questions: 1) is it possible to know if the molecule is double bonded without drawing dots and cross? 2) what happens when the total electrons divided by 2 gives an odd number? Thank you very much.

[@chemistrytutor]

Thanks that's lovely feedback. Yes, for double bonds you need to draw the dot and cross diagram. Or similarly you could look at the number of valence electrons and work out what the electron sharing would be like. E.g. in O2, both oxygen have 6 valence electrons, so both need 2 more for the complete energy level. Therefore they must be doubly bonded. I dont think you'll often have an odd number of electrons, I've never seen an example. Have you?

[@joyam8489]

@@chemistrytutor thank you for explaining.

[@oracle0422]

hey, these videos are very helpful Thank you very much.... I have a request... Can u do a video on equilibria for as and a level pls.

[@chemistrytutor]

Thank you for the feedback! I think I already have this... kzbin.info/www/bejne/nHXUmntsp89qd9k

[@chemistrytutor]

kzbin.info/www/bejne/qqWydo2GpqiDoqc

[@chemmy8062]

Do we have to understand why the shapes construct that way or is it ok to just memorize it?

[@chemistrytutor]

Great question. You need to be able to explain why they form that way. Maximum 2 marks. You need to mention electron pairs repelling to minimise repulsion and so they get as far apart as possible. You also need to be able explain that lone pairs have a greater repulsion

[@madhaviochani6707]

Hello, all your videos are great and extremely helpful. I specifically wanted to ask if you have a video for Dative bond (positive as well as negative ions and some neutral compounds) Also, some metal non-metal bonds are covalent instead of ionic. Would it be possible to have a video on those? Thanks again for the remarkable help you have been giving students

[@chemistrytutor]

Hi, thanks for the kind words. I've got a links document of all my videos. Think you might want the intermolecular forces and Polarity videos? drive.google.com/file/d/19yYWdu3bczjCyeSC-NFp6_V781IRwcvU/view?usp=drivesdk

[@madhaviochani6707]

@@chemistrytutor thanks a lot. I'll check these out

[@bissanyasser5522]

God bless you fr

[@chemistrytutor]

Thanks 😊 Glad you enjoyed it

[@brawlersbrigade1883]

Is this applicable to AS-level aswell?

[@chemistrytutor]

Absolutely, yes 💯

[@synthetic_polymer]

Sir ,can you please explain the molecular shape of nitrite ion?In my book,it is written the bond angles are 120°.But it has 1 lone pair,then shouldn't it be around 117.5°??

[@chemistrytutor]

I agree with you! I think your textbook has simplified the situation. The lone pair would definitely repel the bonding pairs closer together slightly.

[@synthetic_polymer]

@@chemistrytutor thank you so much sir! The teacher now told us that anything between 115-120° is fine😅

[@chemistrytutor]

👍

[@borsalinokizaru731]

This method doesn't work for CO2 right?

[@chemistrytutor]

Not fully, no. For things containing double bonds, you have to treat the double bond as a single electron cloud. So 2 double bonds= linear 2 double bonds and a single bond = 3 electron clouds therefore trigonal planar

[@hudhaifaahmed5738]

thank you so much, this was a great help for my trials!!!

[@chemistrytutor]

Excellent! I'm really pleased to hear it was useful 👍

[@laveshseedheeyan4734]

Thank you sir🙏

[@chemistrytutor]

😀

[@c.stohr14]

This video actually saved me from a mental breakdown- thank you so much!!!

[@chemistrytutor]

I'm really pleased you've found it useful! Hang in there 🙏

[@Gob_123]

At my college we learnt another way to find lone pairs. Group number - number of bonds-charge divide it by 2

[@chemistrytutor]

I like it! Very good method 👏

[@tajwareatswatermelon]

Thank you sir!!

[@chemistrytutor]

No problem 😊 Glad it was useful!

[@PobitroMon]

LIFE SAVERRRRRRRRRR

[@chemistrytutor]

Thanks 😀

[@ahmediftikhar425]

Do you have these notes? thanks in advance

[@chemistrytutor]

I'll look into making the slides into a pdf. It won't have any of the early parts of the slides. It will just be a still of the final view of each slide... is that what you mean?

[@ahmediftikhar425]

@@chemistrytutor Yea, so I wouldn't have to write and I could just look at them when I was revising. No worries though, I have been taking notes.

[@ttc3895]

thx a lot

[@chemistrytutor]

You're very welcome. I'm really pleased it's useful 😀

[@melon_lovers9019]

TY SO MUCH

[@chemistrytutor]

😀👍

[@Leo_BS-ex2xz]

Hi, could you [lease explain a bit more about that nature of the pi bonds that causes double bonds not having a significantly stronger repulsion effect than single bonds?

[@chemistrytutor]

Hi, there isn't much more to it than that. We consider clouds of bonding electrons to have the same repulsion whether they have 2 electrons in it (sigma) or 4 electrons (sigma and pi)

[@Leo_BS-ex2xz]

@@chemistrytutor Oh I see. Thank you very much for answering 😊

[@Haajar_Mahmoud]

Huuuuuuugggeeeeee thanks aaa looooooooot. Extremely useful video.

[@chemistrytutor]

@@Haajar_Mahmoud you're very welcome. Thanks for the feedback 😀

[@safafaridi7443]

How about working out shapes for molecules containing double bonds?

[@chemistrytutor]

Good question. It's not quite so clear cut. When it comes to double bonds you have to consider a double bond as a single electron cloud, so around a carbonyl carbon or an alkene you would consider it to be 3 electron clouds. The 4 electrons in the double bond are considered to have similar and equivalent repulsion to the pair of Electrons in a single bond

[@bronaghmcgilloway9558]

What exam board is this based off?

[@chemistrytutor]

This is based off AQA but I would expect the chemistry to be common across all exam boards

[@nazifarahman5530]

God bless this guy

[@chemistrytutor]

Thanks 😊

[@youremyaddiction3801]

that's it. u r the best

[@chemistrytutor]

Thanks, you're too kind 😇

[@serahaleyabastin]

Is this from as level ??

[@chemistrytutor]

On most courses it is, yes. It's usually taught in the first few months of the first year of A levels

[@studentraphycraigie]

These videos are amazing, thank you.

[@chemistrytutor]

I'm really pleased they're useful for you! 😀

[@saffiyahmajid7882]

is this for AQA?

[@chemistrytutor]

That's what I teach yes, so im certain it's great for AQA. It will also be good for other exam boards as well

[@saffiyahmajid7882]

@@chemistrytutor Thank you, also great video👌

[@armanitwahafa4758]

Amazing✨✨✨

[@chemistrytutor]

Thank you 😊