Here's how to figure out the number of oxygen atoms in copper sulfate:

1. The Chemical Formula:

Copper sulfate's chemical formula is CuSO₄.

2. Subscripts Indicate Number of Atoms:

* The subscript "4" after the oxygen (O) symbol indicates that there are four oxygen atoms in each molecule of copper sulfate.

Therefore, there are 4 atoms of oxygen in one molecule of copper sulfate.