Intermolecular forces

What are characteristics of permanent dipole dipole forces

• Stronger than London forces

• Weaker than hydrogen bonding

• Represented by delta positive/ negative

• Only possible in molecules with permanent dipoles

What are characteristics of hydrogen bonding

• Strongest form of intermolecular force

• Found in when hydrogen bonds to: oxygen, fluorine or nitrogen

• Hydrogen will have a strong permanent dipole dipole with those elements

• Hydrogen has a high charge density due to its small size

How is strength of an intermolecular force determined

• Number of electrons

• More electrons means stronger induced dipole dipole forces

• Larger fluctuations on electron density and leads to stronger temporary dipole and stronger dipole interactions

What are characteristics of induced dipole dipole interactions

• Partial charges exert onto nearby molecules

• Partial charges can push or attract electrons in nearby molecules

• Temporary dipoles will induce dipoles in nearby molecules

• Induced dipoles will be attracted to the original dipole

What are characteristics of temporary dipoles

• Electron clouds around molecules are constantly moving

• Partial charges can change very rapidly

• Electron density is very unpredictable