CHEM 0120 1nd Edition Lecture 3 Outline of Last Lecture I. Chemical BondsII. Acids and BasesIII. Polyatomic Ions Outline of Current LectureI. Dispersion ForcesII. Dipole-Dipole InteractionsIII. Hydrogen Bonding Current LectureI. Dispersion ForcesA. Momentary attractive forces between molecules B. Everything has dispersion forces C. Example: pentane momentary electron position causes attractive forces II. Dipole- Dipole InteractionsA. Structure 1. Polar bondsa. Polar covalent bond with bent structure: net dipole movement b. Polar covalent bond with linear structure: no net dipole movement2. Geometry 3. Same direction and magnitude = add dipoleThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.4. Different direction and same magnitude = cancel dipoleB. Example: Water Contains polar bonds that result in a net dipole movement C. Example: Carbon DioxideContains polar bonds but dipoles cancelIII. Hydrogen Bonding A. Results from interaction between a hydrogen atom bound to a small electronegative atom, such as N, O, F, and a lone pair of electrons on another small electronegative atomB. Strongest intermolecular force C. Example:  Hydrogen