The chemical formula of copper(II) perchlorate is Cu(ClO₄)₂. Here's how we arrive at that:

* Copper(II): This tells us the copper ion has a +2 charge (Cu²⁺).

* Perchlorate: This is the polyatomic ion ClO₄⁻, which has a -1 charge.

To balance the charges, we need two perchlorate ions for every copper(II) ion. Hence, the formula is Cu(ClO₄)₂.