Intermolecular Forces Chapter 16

Intermolecular Intermolecular: Forces between molecules.

Dispersion Forces (aka: London forces, Van der Waals) The weakest attraction. Nonpolar molecules Caused by the motion of electrons Examples: Ar, C8H18 ,halogen diatomic molecules Strength increases as the # of electrons increases

Dipole-Dipole Forces: -polar molecules -molecules with dipoles orient themselves so that “+” and “” ends of the dipoles are close to each other.

Hydrogen Bonds: dipole-dipole attraction in which hydrogen is bound to a highly electronegative atom. (F, O, N)

Which molecules have H-bonding? NH3 CF4 HF

Explain the Difference: H2O Bp = 100°C H2S Bp = -60.7°C

Network Solids Solids in which all of the atoms are covalently bonded to each other Examples: diamond, graphite

Examples of three types of crystalline solids. (a) An atomic solid Examples of three types of crystalline solids. (a) An atomic solid. (b) An ionic solid. (c) A molecular solid.