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Organic Chemistry

Lecture 3 objectives and skills

Objectives

Identify cumulated, conjugated, and isolated p-systems.
Use curved arrows to show electron movement.
Draw and recognize accurate resonance structures and identify the major contributor to the hybrid.
Differentiate between conjugation and hyperconjugation.
Compare cation/anion/radical stability using resonance and hyperconjugation effects.
Rationalize p-system MO diagrams of allylic-type systems, benzene, and butadiene.
Understand the principles behind UV-vis spectroscopy.
Explain differences in wavelength absorption (colour) for various conjugated systems.

Skills

Critical assessment using abstract concepts
Comparisons of fine details
Connection of invisible, microscopic properties to visible, macroscopic observations

This page is referenced by:

Lecture 3: Molecular Orbitals and Resonance 12 image_header 2020-03-21T15:30:09-07:00
Objectives ans Skills

KEY INFORMATION SUMMARY

HERE you can find extra resources to help you with this lecture!

PROBLEMS

Problem 3.1: Resonance Structures
1. Determine whether the following pairs of compounds are resonance structures or structural isomers. SOLUTION
2. 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 l_max 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 ;)