Organic ChemistryMain MenuLecture 1: Introduction to Molecular OrbitalsLecture 10: Intermolecular Forces and Intro to ReactivityLecture 11: Alkenes as Nucleophiles ILectures 12 and 13: Alkenes II & IIILecture 14: Benzenes as Nucleophiles ILecture 15 objectives and skillsLecture 2: Molecular Orbitals in Organic StructuresLecture 3: Molecular Orbitals and ResonanceLecture 4: Molecular Orbitals and AromaticityLecture 5: Nomenclature and IR SpectroscopyLecture 6: Stereochemistry ILecture 7: Stereochemistry IILecture 8: Newman and Fisher ProjectionsLecture 9: Conformations and Cyclohexane RingsJulio Terra2fb22914f73f9e5a767bf7fb83987dca0e153e4a
SOLUTION 3.4
12020-01-28T16:49:29-08:00Julio Terra2fb22914f73f9e5a767bf7fb83987dca0e153e4a359921plain2020-01-28T16:49:29-08:00Julio Terra2fb22914f73f9e5a767bf7fb83987dca0e153e4aBenzene has a higher λmax than CH2=CH2 owing to its conjugated system of double bonds, making the spacing between HOMO and LUMO a smaller energy gap, while the ethene does not have any conjugated doubles, so it has a larger HOMO-LUMO energy gap.
This page is referenced by:
1media/kisscc0-atomic-orbital-computer-icons-chemistry-orbitals-5b7136eca13a03.6431040415341462846604.png2020-01-28T16:26:21-08:00Lecture 3: Molecular Orbitals and Resonance12image_header2020-03-21T15:30:09-07:00Objectives ans Skills
KEY INFORMATION SUMMARY
HERE you can find extra resources to help you with this lecture!
PROBLEMS
Problem 3.1: Resonance Structures
Determine whether the following pairs of compounds are resonance structures or structural isomers. SOLUTION
Insert curved arrows to show movement of electrons between those pairs that are resonance structures. SOLUTION
If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the problem below ;)
Problem 3.2: Resonance Contributing Structures
Draw all the possible resonance structures and predict the best contributing one for each of the following species (include curved arrows). SOLUTION If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the problem below ;)
Problem 3.3: p-Systems
For each of the following species, draw the resonance hybrid and p-orbital view, determine the number of p AOs, p MOs, p-electrons and MOs for the whole molecule. SOLUTION If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the problem below ;)
Problem 3.4: UV-Vis Spectroscopy
Explain why benzene (C6H6) has a higher lmax than CH2=CH2. SOLUTION
If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the next lecture ;)
