sodium chloride
The table salt pictured in the Figure below contains two elements that are so reactive they are rarely found alone in nature. Instead, they undergo chemical reactions with other elements and form compounds. Table salt is the compound named sodium chloride NaCl . It forms when an atom of sodium Na gives up an electron and an atom of chlorine Cl accepts it. When this happens, sodium becomes a positively charged ion Na + , and chlorine becomes a negatively charged ion Cl - . The two ions are attracted to each and join a matrix of interlocking sodium and chloride ions, forming a crystal of salt.