The correct answer is: TO REARRANGE ITS CONFIGURATION TO RESULT IN A COMPLETE OUTER SHELL OR HAVE A STABLE OCTET. Chemical reactions occur because unstable atoms are looking for a way of filling their incomplete outer shells in order to attain stability. Different atoms attain stability in different ways depending on the type of atom it is. Generally, metals prefer to donate their electrons while non metals prefer to accept electrons or share electrons. An atom will become unreactive when the number of electrons in its outer shell is complete.
