Intermolecular Forces M. Billings NSHS

Intermolecular -- ER Force between adjacent (next to each other) molecules produce…cohesion (how well molecules hold to themselves) and adhesion (how well they hold to other molecules).

Adhesion

Cohesion

1. Dipole-Dipole Need 2 polar molecules: the + end of one is attracted to the – end of the other

2. Dipole –Induced Dipole Need 1 polar molecule and 1 non-polar molecule Valence e- on the non-polar molecule move because a polar molecule comes near by

3. Dispersion Forces (Van der Waals Forces) Need a non-polar molecule Random motion of electrons means for an instant you have more electrons on one side of a molecule than another– have a “dipole moment”

Hydrogen Bonding Need –hydrogen in one molecule and high electronegative element (like oxygen or fluorine) Hydrogen ions have no electrons so other atoms electrons are strongly attracted by hydrogen’s nucleus