The table shows the amount of radioactive element remaining in a sample over a period of time.
Radioactive Decay Rate
Amount of Radioactive Sample Time
(grams)
(years)
56.0
0
400
800
1,200
1,600
47.1
39.6
33.3
28
Part 1: What is the half-life of the element? Explain how you determined this.
Part 2: How long would it take 312 g of the sample to decay to 9.75 grams? Show your work or explain your answer.