Intermolecular Forces

• Intermolecular forces can be classified as either permanent dipoles-permanent dipoles (dipole-dipole interactions), induced dipoles-induced dipoles (London dispersion forces), or ionic charges-ionic charges (electrostatic attractions).
• Dipole-dipole interactions occur when one polar molecule is attracted to another polar molecule due to their partial positive and negative ends.
• The intermolecular forces between molecules are the attractive or repulsive forces that exist between two different atoms, ions, or molecules.
• Ionic compounds have strong electrostatic attraction between oppositely charged ions.
• The strength of intermolecular forces depends on the polarity of the molecule, with polar molecules having stronger intermolecular forces than nonpolar ones.
• Induced dipoles are temporary, short-lived dipoles that form between nonpolar molecules.
• Covalently bonded molecules may exhibit weak dipole-dipole interactions if they contain polar bonds.
• The strength of intermolecular forces depends on the size of the atoms involved, with larger atoms having stronger bonds.
• Melting point is the temperature at which a solid changes to a liquid state.
• Boiling point is the temperature at which a liquid changes to a gas state.
• Molecules with larger surface areas will experience more intermolecular forces compared to those with smaller surface areas.
• Ionic compounds have strong electrostatic attractions between oppositely charged ions.
• Covalently bonded molecules may exhibit weak intermolecular forces such as London dispersion forces or hydrogen bonds.
• Electrostatic attractions involve the attraction between opposite charges.
• Nonpolar covalent molecules do not experience any type of intermolecular force.
• London dispersion forces arise from fluctuations in electron density around an atom's nucleus.
• Molecules with no net charge but contain polar covalent bonds experience dipole-dipole interactions.
• Hydrogen bonding occurs when hydrogen is covalently bonded to an electronegative atom such as nitrogen, oxygen, or fluorine.
• Increasing temperature decreases the magnitude of intermolecular forces, causing substances to change state from solid to liquid to gas.
• Molecules with larger dipole moments will experience greater dipole-dipole interactions compared to those with smaller dipole moments.