chlorine is a kind of element & seeing is a mean of part ->  sodium and chlorine are two elements  opening and preserve are one appearance & sodium chloride is made of chlorine and sodium chemically combined -> sodium chloride is made of two elements chlorine and sodium chemically combined sodium chloride is made of two elements chlorine and sodium chemically combined  sodium chloride is made of two elements chlorine and sodium chemically combined & physical pecan are formed by chemically vehicle tunnels -> chemical bonds are formed in sodium and chlorine elements chemical bonds are formed in sodium and chlorine elements  physical birds are formed in balancing and thousands butter & an element is made of one kind of atoms -> chemical bonds are formed among sodium atom and chlorine atoms