Types of Bonds

A. Intramolecular: bonds that exist within a molecule

                -ionic, covalent

B. Intermolecular: bonds that exist between molecules

                -the stronger the intermolecular bonds the higher the boiling point or melting point

                -2 types of intermolecular bonds: Van der  Waasl bonds and hydrogen bonds

I. Van der Waals Bonds

                A. Based on the electron distribution

                                a. 2 categories

                B. Dipole-dipole bonds

                                a. If a molecule is polar the positive end of one molecule will be attracted to the negative end of another molecule

II. London Depression Forces (LDF)

                A. present in all molecules

                B. creates weakest bonds

                C. If a substance is non-polar, dipole-dipole bonds do not exist, only LDFs

                D. Electrons are free to move around and will randomly be grouped on one side of the molecule

                E. This creates a temporary dipole and can cause a weak bond to form

                F. The more electrons in the molecule the stringer the LDF can be

IV. Hydrogen Bonding

                A. If hydrogen is bonded to certain elements (F, O or N) the bond is highly polar

                B. This forms a very strong intermolecular bond