Liquids, Solids, and Intermolecular Forces

Intramolecular forces

within or inside forces (of a molecule)

Intermolecular forces

between molecules

Three important things about IMFs

1. structure of particles determines strength of IMFs

2. particles attracted to each other by electrostatic forces

3. IMFs determine state of the substance

Solids and liquids

relative SHORT distances b/w particles, so IMFs important

Gases

relatively LARGE distances b/w particles, so IMFs negligible

London Dispersion Forces (LDF)

• results from temporary, instantaneous dipoles

• weakest IMF

• ALL molecules have LDF

The stronger the attractive forces among the molecules, the ___ the boiling point will be

higher

Dipole-Dipole Intermolecular Forces

• stronger the polarity, stronger the dipole-dipole intermolecular force

• polarities determined by electronegativities of atoms bonded together and geometry of molecule

Dipole

separation of charge (pos or neg)