How do atoms achieve noble-gas electron configurations in single covalent bonds?

Noble gases are the only type of element that are chemically inert, that is, they do not normally undergo chemical reactions with other elements under normal circumstances, this is because they are chemically stable. Their stability is as a result of the eight valence electrons that they have in their outermost shells.

Other elements usually try to attain the stability found in noble gases by undergoing chemical reactions and by forming different types of bonds with other elements. One of the chemical bonds that are usually formed is covalent bond. In simple covalent bond, two elements usually donate one electron each, the two electrons donated are then shared equally by the two of them in order to ensure that each one has eight electrons in its outermost shell.