[bakins0908]

How do subscripts represent the charge balance of ions

[Perito]

You use superscripts (not subscripts) to represent charge on an ion. Unfortunately, that's difficult to do on this page without special formatting (and I'm too lazy to do that). So, I write Cl- or Cl(-). You just have to remember that charges (+) or (-) are superscripts. Subscripts represent numbers of atoms. So, in sulfuric acid, H2SO4, there are two hydrogen atoms and 4 oxygen atoms. These would be written as subscripts if I weren't so lazy.

Some ions are doubly or triply charged: Sulfate: SO4(-2). Carbonate: CO3(-2). Magnesium: Mg(+2).

When compounds are made from ions, the charges must balance to create a neutral molecule. For example, Mg(+2) combines with two Cl(-) to form MgCl2 (the 2 in this case is a subscript). The subscript indicates that there are two chloride, Cl(-), ions contributing to the compound.