CHM136H1 Lecture Notes - Lecture 7: Lewis Structure, Formal Charge, Organic Chemistry

• School: UTSG
• Department: Chemistry
• Course: CHM136H1

Document Summary

Lewis structures are limited as some electrons can be delocalized. Bonding circumstance requires more than 1 lewis structure. Known as resonance structure where the individuals are blended together. Forms that are most important from most to least. Number of pi-bonds - sharing electrons stabilizes molecules. Structures with most pi bonds make greatest contribution to stability and bonding. Resonance structures w greater charge separation are less important than those that have a closer separation (zero charge is preferred) Important not to ignore the other resonance form - helps with shape etc. In forms with equal formal charges, more important forms have neg charge on more electronegative atom. Inductive effects: e- donating groups help to stabilize (+) charge (below) On far right, a methyl is there - an e- donating methyl, meaning this form is the most stable, better descriptor or the molecule. Important idea: from molecular structure comes everything else. Similarities in structure lead to similarities in properties and behaviour.