How many moles are in 6.73 x 10^24 atoms of cu?

Here is the work, and this will work with any element:

Using the constant 6.022x10^23 for numbers of atoms per mole, we can solve using this simple equation:

Number of atoms of element / mol constant = moles of element

So for this it would be:

6.73 x 10^24 atoms Cu / 6.022 x 10^23 atoms/mol

The atoms cancel and you are left with 11.2 mol Cu

The answer is 323 g.