Here's how to understand the formula:

* Mg: Represents the magnesium ion (Mg²⁺).

* HSO₄: Represents the bisulfate ion (also known as hydrogen sulfate ion), which has a charge of -1.

* (HSO₄)₂: Indicates that there are two bisulfate ions for every magnesium ion, balancing the charges (+2 from magnesium and -2 from the two bisulfate ions).