CHEM1020 Study Guide - Final Guide: Carbonyl Sulfide, Intermolecular Force, Chemical Polarity
Document Summary
Intermolecular forces are the (electrostatic) forces that occur between molecules, or between ions and molecules. They are relatively weak forces, and there is no close approach of atoms as otherwise they repel each other. They are not the strong, short- range bonding forces responsible for covalent or ionic bonds. The last three are collectively k(cid:374)o(cid:449)(cid:374) as (cid:862)(cid:448)a(cid:374) der waals(cid:863) for(cid:272)es. The strength of the interactions decreases down this list. Diatomic molecules are polar if they have a polar bond. Atoms can be thought of as carrying a fractional charge e. g. h+f - which has a polar covalent bond. Separated charges of opposite sign result in a dipole moment as the molecules are polar and they have a tendency to align themselves with an electric field. The size and direction of the dipole moment can be predicted from electronegativity differences. e. g. is co2 polar.