Which of the following transitions are allowed in the electronic emission spectrum of a hydrogenic atom: (i) 2s → 1s, (ii) 2p → 1s, (iii) 3d → 2p?
Ch. 10 Liquids and Solids Intermolecular Forces- attractive forces between molecules; much weaker than intramolecular forces Intramolecular Forces- hold atoms together in a molecule; include covalent bonds, ionic bonds, and metallic bonds Types of intermolecular forces: (from least strong to most strong) a) Dispersion (London) Forces- attractive forces that result from temporary dipoles induced in atoms or molecules; all molecules use dispersion forces; strength increases with molar mass; less surface area = weak attraction; more surface area = stronger attraction b) Dipole-Dipole Forces- attractive forces between polar molecules c) Hydrogen Bonding- occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (F, O, or N). Molecules that can hydrogen bond are usually polar, meaning they are capable of dipole- dipole interactions. Polarizability- the ease with which an electron cloud can be distorted. A highly polarizable atom or molecule can utilize strong dispersion forces Example: Which types of intermolecular bonds are used by the following molecules, and which bond is strongest a) N 2 dispersion forces; dispersion strongest b) CO – dispersion, dipole-dipole; dipole-dipole strongest c) CH 3H – dispersion, dipole-dipole, hydrogen bond; hydrogen bond strongest d) CH 3CH – 3ispersion, weak dipole-dipole; dipole-dipole strongest Liquid State Properties- surface tension, viscosity, and capillary effect (cohesion and adhesion). Surface Tension- the amount of