1.3 Valence Bond Theory and Hybridization | Organic Chemistry
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- čas přidán 16. 06. 2024
- Chad goes over Valence Bond Theory and Hybridization covering both the standard atomic orbitals as well as the hybrid orbitals that may be involved in bonding. He specifically shows the nature of sp, sp2, and sp3 hybrid orbitals and how to identify the hybridization of an atom. Finally, Chad compares and contrasts sigma bonds and pi bonds, how to recognize where each are present in a structure, and how to identify which orbitals are overlapping to create a particular bond.
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00:00 Lesson Introduction
00:31 Introduction to Valence Bond Theory and Atomic Orbitals
03:31 Sigma Overlap and Sigma Bonds
06:36 Pi Overlap and Pi Bonds
08:11 How to Identify the Hybridization of an Atom
12:17 sp, sp2, and sp3 Hybridization
21:08 Identifying which Orbitals Overlap to Create Bonds
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Bro been having multiple panic attacks and the semester hasn't even started. My OG teacher isn't the best so I now I have to result to CZcams University. Thanks so much Chad, you're the best!
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Great videos! great explanations!
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You re indeed a teacher.. thanks for your efforts
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That was super informative and clearly and simply explained so thanks a lot!
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You explain this better than my chemistry professor
Glad you found us, Toker!
Thank you so much! You seriously are helping a lot of students and reducing stress:))
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Thanks you so much Mr lecture,you made me understand this topic very well rather than before ,otherwise be bless
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Thank you Chad!!! I'm retaking organic chem right now and your videos are definitely giving me the information I need to ace this second try!
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most amazing teacher ever!
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Chad you saved my life in gen chem and you're saving me now in organic. Thank you for your commitment, God bless you!!!!!
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I better be smiling in that Prometric centre like an hyena ...just cause professor Chad is my YT tutor. Can’t wait to ace that DAT and come back with my testimony.
Awesome Christianah! And have you seen my DAT Practice Exams? They're still available free of charge for a little while longer!
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Valence Bond Theory
Concept: Valence bond theory explains covalent bonding through the overlap of atomic orbitals. Electrons are shared in these overlapping regions.
Atomic Orbitals:
1s Orbital: Spherical shape.
2p Orbital: Dumbbell shape with a node at the nucleus.
Overlap Types:
Sigma (σ) Overlap: Occurs along the internuclear axis (the line connecting the two nuclei).
Pi (π) Overlap: Occurs side-to-side and involves p orbitals only.
Examples of Sigma and Pi Overlap
H2 Molecule: Sigma overlap of two 1s orbitals.
HF Molecule: Sigma overlap of hydrogen’s 1s orbital with fluorine’s 2p orbital.
F2 Molecule: Sigma overlap of two 2p orbitals.
Pi Overlap: Only involves p orbitals and occurs above and below the internuclear axis.
Hybridization
Concept: Hybridization is the mixing of atomic orbitals to form new hybrid orbitals that can form stronger, more stable bonds.
Determining Hybridization:
Electron Domains: The number of atoms bonded to and lone pairs around an atom.
Types:
sp3 Hybridization: Four electron domains, bond angles of 109.5°.
sp2 Hybridization: Three electron domains, bond angles of 120°.
sp Hybridization: Two electron domains, bond angles of 180°.
Examples of Hybridization
Methane (CH4): Carbon is sp3 hybridized with four sigma bonds, bond angles of 109.5°.
Ammonia (NH3): Nitrogen is sp3 hybridized with three sigma bonds and one lone pair, bond angles slightly less than 109.5° due to lone pair repulsion.
Formaldehyde (H2CO): Carbon is sp2 hybridized with three sigma bonds and one pi bond, bond angles approximately 120°.
Acetylene (C2H2): Carbons are sp hybridized with a triple bond (one sigma and two pi bonds), bond angles of 180°.
Practical Applications
Sigma Bonds: Formed by overlapping hybrid orbitals or atomic orbitals.
Pi Bonds: Formed by the sideways overlap of unhybridized p orbitals.
Lone Pairs: Reside in hybrid orbitals if the atom is hybridized.
You're so helpful 🙂 youre pretty much my substitute teacher rn ❤❤
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Thank you so much❤️❤️❤️
You're very welcome Imanish! Glad you're finding these helpful!🙂
Chad you are my king
King? I certainly hope not!😜 How about short, bald, helpful YT instructor? But I appreciate the sentiment!😊
For the F2 example did you mean their valence electrons are in the P orbital not S?
I think so, I came here to say the same thing 😂
you're amazing. thanks a ton.
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Chad goated for this one
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God bless you Sir
Thank you.
omg thank you so much i dont know why i didn't found this before my exams but i hope i can get a good grade on the final exam so i can pass:C
You're welcome - glad you found the channel!
I'm not sure I understand overlapping orbitals. In methane, for example, each H shares a pair of electrons with the C. In one of those pairs, do the two electrons have identical wave functions (except for spin)?
Hey Fred! First of all, keep in mind that Valence Bond Theory has its shortcomings...it's an incomplete theory but still has its utility. But it sets the stage for molecular orbital theory (the next lesson I'll be releasing later today). The main idea was that when two atoms bond together their electron clouds overlap to form a giant electron cloud that encompasses both atoms. Note my use of the word cloud instead of orbital just to give it a little different feel.
In Molecular Orbital theory we'll find out the when two orbitals (which are depictions of wave functions) overlap they actually combine to form a new orbital (a new wavefunction). So we could say that the overlap of the Atomic Orbitals leads to the creation of a new Molecular orbital. But you'll see that even this explanation is too simplistic as the overlapping atomic orbitals will actually result in the creation of TWO molecular orbitals: one bonding and one antibonding.
And if you get to molecules having more than two atoms it gets even more complicated, but we will largely ignore that in organic chemistry with one exception when we study conjugated systems (usually in the 2nd semester).
Hope this helps!
@chad, concerned about the idea of a carbon atom ‘investing’. It cant do that, so what’s the mechanism? Dont need to explain, just give me the buzzwords and I’ll research it myself. Thanks for great content.
I have a question. Towards the beginning of the video, in the H-F and F-F bonds, would it not be overlap between s (for H) and sp3 (for F), instead of p for F? I thought F would have sp3 hybridization, and thus it would be an sp3 hybridized orbital overlapping with the s orbital from H as opposed to a pure p orbital from F overlapping with the s from H. And then F-F would have overlap between two sp3 hybridized orbitals, instead of overlap of two p orbitals.
Great question Laura! It turns out that only atoms that are making more than one bond experience hybridization. With F only making one bond, it simply used the atomic orbital where we find its unpaired electron, a 'p' orbital. So while you might look at the Lewis structure and see 4 electron domains and think sp3, F is not hybridized and is just using a 'p' orbital.
The worst part of all of this is that when you get to molecular orbital theory, you'll learn that while the idea of hybrid orbitals has great utility in predicting bond angles and molecular geometry, it isn't an accurate reflection of reality in other ways (predicting energy levels of orbitals). So the theory does have some explanatory power, but molecular orbital theory has even greater explanatory power and is 'more' correct. So hybrid orbitals may not even really exist :(
Hope this helps!
@@ChadsPrep Good to know, thank you very much for your reply!
@@lauraj2815 👍👍👍
If the negative side of the orbital hits the positive side of the other orbital then they don't form a bond? What makes it positive or negative?
Hi Pablo! I go into that in greater detail in the very next lesson on Molecular Orbital Theory: czcams.com/video/PZCsJH1taYA/video.html
Take a look and let me know if I didn't answer your question to your satisfaction there. Happy Studying!
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Thank you - Happy Studying!
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@@ChadsPrep We students love when teachers actually know how to educate and not just school kids!
Sir can you explain me about the role of entropy in dissolving process? It is not relevant to your videos 😶
Yes - briefly, anything that increases the disorder of a system increases entropy. When a solute dissolves it increases the disorder of the system because solute particles separate and become dispersed in the solution. So dissolving increases entropy.
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😁😁😁 Good luck!