How many moles of magnesium is 2.77 x 10^24 atoms of magnesium?

4.6 moles.

Explanation:

To find the amount of moles of Magnesium, you will need to use Avogadro's number to convert between the two units.

2.77*10^24 moles Mg * (1 mol Mg) / (6.02*10^23)) ≈ 0.46*10^1 moles which equals 4.6 moles.