CHEM 2331H Lecture Notes - Lecture 9: Lone Pair, Ionic Bonding, Partial Charge

• School: UMN
• Department: Chemistry
• Course: CHEM 2331H
• Professor: T.Andrew Taton

Document Summary

When electronegativity difference is too big, the more electronegative atom just takes the electron not sharing, transferring ionic bond. N normally owns 5 but in nh4, owns 4 5 4 = +1: ex: hydroxide: o has 1 bond and 3 lone pairs formal charge of -1. 6 7 = -1: tip: when # of bonds varies from typical valency, atom is probably charged, example: 1st one: carbon doesn"t have filled octet bad. 2nd one: oxygen is positive even though it is more electronegative . better to have carbon be positive. Consensus structure: graphical average of both structures. Use partial charges rather than exact fractions because haven"t weighted which resonance structures is better . don"t know which one is more dominant. Bond is also between length of single and double bond 1 solid bond and 1 dashed bond. Don"t draw lone pairs in consensus structures. Major and minor resonance contributors: resonance rules of thumb (with 1st being most important rule):