Answer:
After 1 half-life (500 years), 500 g of the parent isotope will remain. After 2 half-lives (1000 years), 250 g of the parent isotope will remain. After 3 half-lives (1500 years), 125 g of the parent isotope will remain. After 4 half-lives (2000 years), 62.5 g of the parent isotope will remain.
Explanation:
