7.1: Chemical Bond 7.2: Electron Dot Diagrams 7.3: Octet Rule 7.4: Cation Formation 7.5: Anion Formation 7.6: Ionic Bonding 7.7: Polyatomic Ions Many materials exist as simply binary compounds composed of a metal cation and a nonmetal anion, with each ion consisting of only one type of atom. Other combinations of atoms also exist, either larger ionic complexes or complete molecules. Some of the most useful materials we work with contain polyatomic ions. 7.8: Covalent Bond 7.9: Lewis Electron-Dot Structures 7.10: Single Covalent Bonds 7.11: Multiple Covalent Bonds 7.12: Valence Electrons Valence electrons are the electrons in the highest occupied principal energy level of an atom. In the second period elements, the two electrons in the 1s sublevel are called inner-shell electrons and are not involved directly in the element's reactivity or in the formation of compounds. 7.13: Coordinate Covalent Bond Each of the covalent bonds that we have looked at so far has involved each of the atoms that are bonding contributing one of the electrons to the shared pair. There is an alternate type of covalent bond in which one of the atoms provided both of the electrons in a shared pair. 7.14: Resonance Resonance is the use of two or more Lewis structures to represent the covalent bonding in a molecule. One of the valid structures is referred to as a resonance structure. It is now understood that the true structure of a molecule which displays resonance is that of an average or a hybrid of all the resonance structures. 7.15: VSEPR Theory 7.16: Molecular Shapes- No Lone Pairs on Central Atoms 7.17: Molecular Shapes - Lone Pair(s) on Central Atom 7.18: Bond Polarity 7.19: Polar Molecules