I just entered university chemistry and my teacher didn't explain this topic very much so I was really confused - Thank you for explaining it so well! Much luck to you and your channel!
Thank you so so much! This was really helpful and I saw this video on the website but just had to watch this on youtube to give it a thumbs up and a comment of appreciation. Thank you!!
Thank you very much!!! I was learning about Lewis structure and resonance form but i've got no idea why Sulphur could expand its outermost electron shell. And after watching your video I finally has a clear understanding of it!!! Love your clear explanations and notes 🥰
This was so helpful, now I can finally move onto the next section of my book - I was writing the Lewis structure of SF6 because the textbook said so but my mind was rejecting it every time and I just couldn't really move on because I could not grasp why this made sense when there were only 2 unpaired electrons for sulfur at ground state. THANK YOU!
Thank you so much! My teacher leaves these complex things blank for the sake of simplicity, but it bothers me. Now I understand it and can finally remember how bonds work!
As far as i know his explanation is probably wrong though. The expansion into the d-orbital is not accepted anymore as described by wikipedia and the encyclopedia britannica and many other source (see hypervalance).
09:43 Wait, this electron was spin down before, and now it's spin up. Can electrons flip their spin just like that? I've been always told that a particular spin is an innate property of an electron. 14:24 How much is "too big"?
Thank you! The process of excitation or unpairing electrons and promoting them to higher energy orbitals requires a bit of energy, but will be compensated when more covalent bonds can be formed and more energy is released.
Thank you for this informative video. I have a question if that is okay, you mentioned 13:12 how the greater the number of bonds --> the greater the overall stability, however you earlier mentioned 09:09 that "I am trying to put this electron from a stable state to a less stable state". Could you please clarify whether or not octet expansion actually leads to greater stability or not?
During excitation, electrons are unpaired and placed in orbitals of higher energy so the excited state is less stable than ground state. But the unpaired electrons will now be able to form more covalent bonds which is exothermic so the final outcome will be more stable. So in short there will be a net increase in stability if an element can expand octet.
Notes: expanded octet is the norm not the exception. Periods 3 and beyond's electrons have access to 3d orbitals through excitation More bond formation is better because more energy is released.
interestingly 4s orbital has lower energy than 3d when empty. When electrons occupy 4s and 3d subshells the energy level is reversed: 3d subshell is more stable than 4s subshell. That's why when we write out electronic configuration we write 3d first followed by 4s. So electrons will be promoted to 3d subshell instead
@@ChemistryGuru I didn't understand , if you don't mind can you explain what happens if the electrons were promoted to 4s instead of 3d please . Thank you .
@@sarayyaragu9382 when electrons are added to 4s and 3d subshells, the energy levels of the 2 subshells are reversed. When empty, 4s is more stable than 3d When filled, 3d is more stable than 4s
Isn't this explantion wrong? Wikipedia and the encyclopedia britannica tell me that the theory of an expansion into the d-orbitals is wrong and not accepted anymore (d-orbitals don't play a dominant role).
The concept that is acceptable depends on the syllabus. For A Level Chemistry we can use what I've discussed in the video to understand how expansion of octet works.
@@ChemistryGuru Shouldn't we mention on every level, when an explanation is usefull, but wrong? We can still teach the concept, but we should add that it's wrong, don't you think? Like when we teach the Bohr model. We usually mention, that it's wrong and that electrons don't move in circles around a nucleus.
@@stauffap as teachers we can't just teach the most advanced concepts to the beginning students. That's what the syllabus is for, to set the appropriate concepts at appropriate levels for students at different level. I'm a tutor for A Levels so the concepts that I teach and discuss in the channel is for concepts appropriate and suitable for A Level syllabus. There's nothing wrong with that.
