Intermolecular Forces

• Dipole-dipole forces are the attraction between opposite dipoles of polar molecules
• Dipoles tend to move away from repulsive orientations and maintain attractive orientations
• Dipole-dipole are only for polar molecules
• London forces are when instantaneous dipoles in nonpolar molecules provide weak attractive forces
• London forces= dispersion forces= instantaneous dipole forces= induced dipole forces
• The unevent distribution of electrons will induce dipoles in the molecules surrounding the molecule
• Noble gases contain london forces and have very low boiling points
• Hydrogen bonding occurs when hydrogen is bonded to oxygen, flourine, or nitrogen
• Large electronegativity of oxygen, nitrogen, and fluorine explain hydrogen bonds
• HF and NH3 form chain structures
• Water forms a network structure
• Hydrogen bonding explains why water is liquid at room temperature, why ice is less dense than water, and DNA double helix
• Nonpolar = London forces
• Polar= Dipole-dipole forces
• HF, HO, HN= hydrogen bonding
• Van der Waals forces include london, dipole-dipole, and hydrogen bonding