The small number behind each element symbol designates the number of atoms of each element in a chemical formula. If there is no number, it is assumed there is only one of those elements. A large number designates how many units there are of that compound.
The small number behind each element symbol indicates each element's number of atoms in a chemical formula. If there is no number, it is assumed there is only one of these elements. A huge numeral in front of a compound designates whereby many units there are of that compound.
