The ratio of elements in a compund is shown by the subscript number beside the elements in the compund.

The subscript number represents the number of atoms each element gives to form 1 mol of a compound.

As in Al

or in NaCl is 1:1

The subscript number represents the number of atoms each element gives to form 1 mol of a compound.

As in Al

_{2}O_{3}shows that the ratio of Al to O is 2:3or in NaCl is 1:1