Construct from models single, double, and triple bonded molecules. Measure the bond length from nucleus to nucleus. Determine why the bond lengths are different. Elicit the general rule that as bond length decreases, bond strength increases. Define the energy of dissociation, elicit the relationship between the bond length and the energy of dissociation. Discuss how the total energy of a compound is determined. Define endothermic and exothermic compound formations.