Chapter 4: Resonance

Learning Objectives:

• Understand why we have / need resonance
• Be able to draw and recognise resonance structures efficiently
• Be able to rank resonance structures
• Show how resonance affects properties, reactions etc.

Summary

Resonance is a very important concept and tool for organic chemistry... if resonance is there, then it usually controls the outcome. So it is important to be able to recognise when resonance is present and to know what it does.

• Why do we need resonance ?
• Why is resonance important ?
• Terminology
• Resonance contributors and resonance hybrid
• The Orbital Perspective
• Rules for recognising resonance structures
• Rules for ranking resonance structures
• Resonance in action

Problems

• Sample questions

© Dr. Ian Hunt, Department of Chemistry