predicting dipole moments/boiling and melting point trends

how to: dipole

1. predict 3D structure

2. identify polarized bonds

3. are bonds symmetrical?

how to identify polarized bonds

one of the two atoms is EN

what happens if there is symmetrically between the bonds

they’d cancel each other out and there’d not be a molecular dipole

a tetrahedral molecule is symmetric when

all 4 bonds are the same

a trigonal planar molecule is symmetric when

all 3 bonds must be the same

Stronger attractive forces

Higher MP and BP

Ion-ion

• 1

• Positive charges and negative charges

• Anions and cations

Ion-dipole

• 2

• Anions or cations with molecular dipoles

Hydrogen bond

• 3

• Special dipole-dipole with acidic hydrogen

• Alcohols, amines, carboxylic acid, carboxylic amides

Dipole-dipole

• 4

• Attraction of partial positive and partial negative charges

• Nitriles, ketones, aldehydes, carboxylic esters, alkyl halides

London dispersion forces

• 5

• attraction of random dipoles

• Alkanes, alkenes, but all molecules can form these-strength related to surface area

ho, carol am crazy oh, crazy aye

alcohol, amine, carboxylic acid, carboxylic amide

hydrogen bonds

no aldi, course everything ain’t here, dum-dum

nitrile, aldehyde, carboxylic ester, alkyl halide

dipole-dipole

lawd, aye aye, no why

london, alkanes, alkenes