Page 2: Van der Waals Forces and London Dispersion Forces

This page delves into the various types of van der waals forces and their significance in molecular interactions, including dipole interactions and London dispersion forces.

Definition: Van der waals forces are intermolecular forces resulting from temporary electron distribution changes, encompassing several types of molecular interactions.

Example: Gecko feet demonstrate practical application of van der waals forces, enabling them to adhere to smooth surfaces through molecular interactions.

Highlight: London dispersion forces are the weakest type of intermolecular force but are universal, affecting both polar and nonpolar substances.

Vocabulary: Dipole-induced dipole interactions occur when polar molecules influence electron distribution in nearby nonpolar molecules.

Example: The strength of London dispersion forces increases with molecular weight, explaining why heavier compounds have stronger intermolecular attractions.

Page 1: Fundamental Forces and Hydrogen Bonding

This page introduces the crucial distinction between intramolecular vs intermolecular forces. Intramolecular forces operate within molecules through covalent or ionic bonds, while intermolecular forces function between molecules, affecting substance properties.

Definition: Intramolecular forces are the strong bonds that hold atoms together within a molecule, primarily through covalent or ionic bonding.

Highlight: Intermolecular forces are significantly weaker than chemical bonds but play a crucial role in determining physical properties.

Example: Water demonstrates strong hydrogen bonding, leading to:

• Higher melting and boiling points
• Increased surface tension and viscosity
• Excellent solvent properties for polar substances
• Unique density characteristics where ice floats on liquid water

Vocabulary: Hydrogen bonding occurs when hydrogen, bonded to an electronegative atom, is attracted to another electronegative atom of a different molecule.