5A Alkenes - Edexcel IAS Chemistry (Unit 1)

[@zerolahmachun7372]

YOU ARE SUCH A LIFE SAVER. YOU EXPLAIN EVERYTHING SO WELL. YOU HAVE SAVED ME AND MY GRADES. I UNDERSTAND EVERYTHING THANKS TO YOU. BLESS YOUR SOUL. THANK YOU SO MUCH. KEEP DOING WHAT YOU DO PLEASE.

[@losttrash980]

hello which uni r u in now

[@Miko-orginal-1]

My attention span is deteriorating because a levels are so hard

[@celdrix8382]

how are things now

[@rafiatbm7867]

Miss...A question regarding stuffs at around 5:00...Although we're learning this we haven't learnt about how the covalent bonding takes place in the organic compound actually, Let's take CH4 as an example What I am saying is that, if carbon stays like C(6) = 1s2, 2s2, 2p2 (electronic configuration we learned), it cannot form covalent bond as 2 orbitals are full filled, and we know covalent bonding is formed by overlapping of two half filled orbitals My question is then does carbon becomes like this, i.e. C(6) = 1s2, 2s1, 2p3 in order to form the 4 covalent bonds....like then the S, Px,Py & Pz orbitals are half filled and this then should allow the organic compound CH4 to be formed ?

[@MissNatalieChemistry]

This is a great question. It is actually a slightly more complicated method that is out with the scope of A Level but is still useful to know. One of the 2s orbital electrons is promoted to the empty 2pz orbital to allow 4 bonds to be made. The problem with this is that the orbitals are now all different energies so they undergo a process called hybridisation to form 4 sp3 orbitals (a combination of 1 s orbital and 3 p orbitals). Now that there are 4 sp3 orbitals of the same energy, they can overlap with the s orbitals form hydrogen and form the covalent bonds. The link below from chemguide is also a very good description along with diagrams: www.chemguide.co.uk/basicorg/bonding/methane.html# I hope that helps!

[@rafiatbm7867]

@@MissNatalieChemistry So I actually assumed that thinking about the chemistry of the electronic configurations of chromium and copper... It turned out to be right!! So yeah that's what happens but how is exactly is that thing (the transfer of an electron to the Pz orbital) compatible is something that is not in our syllabus...Got the point..Thanks!!

[@rafiatbm7867]

Another question miss...😅 Referring to discussion at 17:40 and electrophylic attack.. You said electrophiles will attack in an area of high electron density, which is the reason why they attacked the double bond.. My question is, the bonded atoms also has high electron density around in the line joining the centres of two atoms (the sigma bond basically) along with having high electron density above and below the line joining the centres of two atoms (The pi bond basically)... Then why do electrophiles choose to attack the pi bond of a carbon-carbon double bond and not the sigma bond?? The reason I gave referral to the lines is because I think the answer is like this that it something to do with the placement of bonding electrons between the centres... But not getting why exactly the pi bond !!

[@MissNatalieChemistry]

The main reason is that the electrons in the pi bond are more exposed than the sigma bonds as they are located above and below the sigma bond. So essentially the pi bond electrons are the one the electrophile reaches first so they are the ones that will take part in the reaction.

[@tuleenbadran4477]

miss on 22:24 step 1 is suppose to be h-br and not br-br right ?

[@MissNatalieChemistry]

It should be Br-Br as this mechanism is the addition of a halogen not a hydrogen halide. You need to know both examples.

[@Miko-orginal-1]

I’m stressing 💀💀

[@Mollymae-l1y]

miss do i also have to know about the oxidation of alkenes in hot concentration of kMno4

[@nishabiswas9325]

Miss , are we expected to know how to draw the diagram in 4:57

[@MissNatalieChemistry]

You could be asked to draw this as it is a good way to get all 2 marks in a question asking for how the bonds form. You can either draw them together like this or separately.

[@shobarbaba]

hello miss! may i know why cycloalkenes have a different general formula from normal alkenes?

[@user-zt1xj5vk4z]

cause they just do

[@ShokoIeiri-j7d]

Thank u so much ur so amazing ❤❤❤

[@thiumini4152]

Ma'am ,thank you very much for this wonderful explanation, in question two, when bromine reacts with propene, can it also be called a halogenation reaction instead of electrophilic addition?

[@leilasumerville6452]

Thank you!!!!!!!!!

[@muhammadraid1925]

Do we have to memorize the formulas for the electrophilic addition reactions or just the statements

[@fishyamy5564]

Miss why does pi bond have a lower electron density ?

[@MissNatalieChemistry]

It doesn't. Pi bonds have a high electron density, but since the electrons exist above and below the carbon atoms instead of in between them (like in sigma bonds), they are more easily broken.

[@aysha9883]

Hi miss, thank you for this video. Could you explain a little bit more about how a carbocation is formed?

[@Miko-orginal-1]

Rip me 😭