CAS CH 102 Lecture Notes - Lecture 28: Covalent Bond, Molecular Geometry, Intermolecular Force
Document Summary
Covalent bonds: share of e-s: nonpolar covalent bond: electro negativity difference between atoms is 0. Symmetrical distribution = nonpolar: polar covalent bond: electro negativity difference is between 0. 4 and 1. 6; not an equal sharing of e-s; e- s are more attracted to more electronegative atom. Asymmetrical distribution = polar: polar molecules are also called dipoles; molecules with + and charges, usually gases, and liquids/solids with low boiling pints, does not conduct electricity. Metallic bonds: strong attraction between differently charged particles; positive ions in a sea of electrons: high melting points, great strength, good conductors of electricity. Intermolecular forces = van der waals forces; attraction between molecules not atoms. Weak intermolecular forces = low boiling points. Dipole-dipole attraction: force of attraction between polar molecules; positive end of one dipole attracts negative end of another. London dispersion forces: sometimes nonpolar particles become polar because of constant motion that causes uneven charge distribution, so it is temporarily a dipole.
