The combination of symbols that shows the ratio of elements
in a compound is called chemical formula. A chemical formula is one of the ways
in expressing information about the ratio and proportion of atoms that consists
a particular chemical compound. This is done by using a single line pf chemical
symbols of elements, numbers, and sometimes parentheses, comma, dashes,
brackets and sometimes the positive and negative sign. Chemical formula can
completely specify the simplest structure of molecules and chemical substances.