CHEM 1A Chapter 2: Covalent Bonding
Document Summary
Octet rule: atoms share electrons until they reach a noble gas configuration (8 valence e-) Less electronegative (lowest ionization energy) atom is the central atom. A large electronegativity difference results in an ionic bond. A small electronegativity difference results in a polar covalent bond. A difference of zero in electronegativity results in a nonpolar covalent bond, which is sometimes referred to as a true covalent bond. Resonance: a blending of multiple lewis structures into a single composite using a double arrow. Resonance lowers the energy below that of the contributing structures in order to stabilize the molecule. Nuclei are always in the same position; only locations of lone and bonding pairs changes. Low-energy (formal charge) structures contribute more to the resonance mixture. Resonance hybrid: the composite structure that results from resonance. Delocalized: shared electron pair is distributed over several pairs of atoms and cannot be identified with just one pair of atoms.
