ABSTRACT
Proteins, sugars, and other important biological molecules are collections of atoms held together by a force of attraction called covalent bonding. Covalent bonds are formed between atoms that can share electrons to achieve a full shell of electrons. Such a full shell is a very stable structure. When two atoms move toward one another, the outer-shell electrons in each rearrange themselves to reduce their potential energy. The energy falls to a minimum when they are a specic distance apart. This distance, when measured between the two atomic nuclei, is called the bond length. The fall in energy that has occurred is the bond energy (Figure 2.1).
