Types of IMFAs 1. London or Dispersion Forces 2. Dipole-Dipole Interactions 3. Hydrogen Bonds 4. Ion-Dipole London Dispersion Forces - Temporary or weak dipole interactions (such as those between nonmetals) in nonpolar compounds Named after Fritz London Dipole-Dipole Interactions - Permanent or strong dipole interactions (such as those between nonmetals) in polar compounds is indeed the molecular force driving the molecules to be soluble with one another and stay in solution Hydrogen Bonds - are intermolecular forces of attraction that form between the positive dipole of a hydrogen atom of one molecule and the partially negative dipole of fluorine (F), oxygen (O), and nitrogen are simply very strong and very specific dipoles, which makes them the second-strongest intermolecular force of attraction, second to ion-dipole interactions. dipoles are stronger because they occur between hydrogen which has a very low electronegativity level and atoms of F, O, and N that have very high electronegativities. The disparity between the atoms’ desires to obtain electrons creates a strong force of attraction. Ion-Dipole Interactions - Are the forces that exist between an ion(cation or anion) and a polar molecule For example, the partially positive dipole of hydrogen in water as it interacts with a fully charged chloride anion. When sodium chloride, NaCl, is added to water to form a solution, the sodium and chlorine dissociate and form the Na+ cation and the Cl – anion. The chloride ion is then attracted to the positive dipole of hydrogen and the sodium ion is attracted to negative dipole of oxygen. Because the interaction is between a fully charged ion and a partially charged versus two partially charged dipoles, ion-dipole interactions are the strongest IMFA, even greater than hydrogen bonds. Polar Non-polar One or more terminal atoms differ from each All of the terminal atoms or groups are the same other At least one polar bond is present All of the terminal atoms or groups are symmetrically arranged The terminal atoms are not symmetrically The terminal atoms or groups have the same arranged charges The molecule has one slightly positive end and negative end One of the most distinguished scientists on the Duke University faculty. He was an internationally recognized theorist in Chemistry, Physics and the Philosophy of Science. He was born in Breslau, Germany (now Wroclaw, Poland) in 1900.
