CHEM-UA 225 Chapter 1: Summary of Ch. 1
Document Summary
Essential skills and details: writing lewis dot structures for atoms, ions, and neutral molecules, determination of formal charge, writing resonance forms, using curved arrow formalism, sign conventions for exothermic and endothermic reactions. Resonance forms: many molecules are incompletely represented by just one lewis structure. For these molecules, resonance structures will provide a more accurate description: resonance forms are different electronic representations of the same molecule, resonance forms are not species in equilibrium--molecules do not oscillate back and forth between resonance forms. The more accurate structure of the molecule--called the resonance hybrid--is the weighted average of all forms: some resonance forms contribute more than others to the resonance hybrid. Molecular orbitals: overlap of two atomic orbitals produces two new molecular orbitals, one bonding and the other antibonding, two electrons can be accommodated in the lower-energy bonding molecular orbital. In this way, two atoms (or groups of atoms) can be bound through the sharing of electrons in a covalent bond.
