Intermolecular Forces (IMFs)

Ion-induced Dipole Forces

• Weak attraction between ions & non polar

• Approach of ion causes TEMP Dipole

• Cause: electrons are disturbed and shift

  (Unequal distribution)

Dipole-Induced Dipole Forces

• Weak attraction between polar & non polar

• Polar molecule causes TEMP Dipole to form in an atom or nonpolar substance

• Electrons are disturbed and shift

Polarizability

Idea: electron cloud is distorted because of shifting electrons that create TEMP Dipole

(Pi bonds - electrons move more easily in a pi bond)

(Induced dipoles are harder to achieve in bulky, branched molecules {cannot easily approach})

Describes strength in IMF’s

Ion-Ion Force

• F of A between Ions within crystal lattice of ionic compound

• Very strong

Van der Waal’s Forces

General term to describe a group of IMF types

(Dipole-dipole, London Dispersion, dipole-induced dipole)

London Dispersion Forces (LDFs)

• When TEMP dipoles form cause of shifting electrons

• Sometimes called induced dipole

• Weakest IMF but strength increases with MORE electrons

LDFs

• only IMF between nonpolar and noble gases

• Distinguishabl