CHEM 122 Midterm: Chemcram Midterm Review

• School: McGill University
• Department: Chemistry
• Course: CHEM 122
• Professor: Laura Pavelka

Document Summary

Organic chemistry is concerned with organic molecules and reactions of organic molecules. Chemical reactions are really just electrons moving around. In forming a new bond between atoms you transfer electrons from each atom to be shared. Individual electrons are hard to locate (heisenberg"s uncertainty) so chemists fin it easier to consider orbitals when considering how the electrons in two atoms will interact. Orbitals maps of the 3d area around the nucleus with the highest probability of finding the electron (90-95%) Atomic orbitals describe where the electrons are in non-bonded, individual atoms. When atoms interact (and their atomic orbitals interact) bonds are formed, and the atomic orbitals are replaced by molecular orbitals. Like atomic orbitals, molecular orbitals represent the 2d area with the highest probability of finding the electron. Molecular orbitals are spread over the entire molecule. So organic chemists often take a step back and use concepts from valence bond theory to explain the behaviour of certain molecules.