WARM UP How do you determine if a bond is ionic, polar covalent, or nonpolar? How do you determine if an entire molecule is polar or nonpolar? Draw a water molecule, indicating the + and – ends.

Intermolecular Forces

Video Demonstration

IMF Overview Force of attraction between + and – in separate molecules Weaker than actual bonds Coulomb’s Law Larger charge or polarity, larger intermolecular force Charles Coulomb

IMF Overview Polarizability Ability of a nonpolar atom or molecule to become polar Temporary and weak charge Induced by an outside charge More e- = higher polarizability = more charge

IMF Overview Studied by Johannes van der Waals Fritz London Covalent forces (gases) Fritz London Dispersion forces

Ion-Ion Ions in crystals NaCl

Dipole-Dipole Opposite ends of polar molecules

Hydrogen Bonds Very strong dipole-dipole Adjacent H and O/N/F attract H bonded to O, N, or F Adjacent H and O/N/F attract

Ion-Dipole Ion and polar molecule Salt water

Ion – Induced Dipole Ion and nonpolar

Dipole – Induced Dipole Polar and nonpolar O2 in water

Dispersion / London (a.k.a. induced dipole – induced dipole) Two nonpolars CO2 Random e- movement creates temporary dipoles

WRAP UP Explain the term polarizability, using an example.

WARM UP List 5 different intermolecular forces, and write a 3-word description of each.

WRAP UP NH3 and NH3 CaF2 and H2O NaCl and H2 O2 and N2 Identify the intermolecular forces present in each of the following mixtures: NH3 and NH3 CaF2 and H2O NaCl and H2 O2 and N2