Question

What do the subscripts mean in a chemical formula?

Answer 1

It indicates that there are a certain number of atoms in a compound.

For example:

`Al_2(SO_4)_3`

This shows that there are three times the number of atoms which are in the brackets:

S - 1 x 3 = 3 atoms
O - 4 x 3 = 12 atoms

Hope this helps!