The half-life of iodine-131 is 8 days. chan hee examines two samples of iodine-131. sample 1: 10 g sample 2: 20 g what can chan hee expect to observe about the samples after 16 days? a. the mass of iodine-131 in sample 1 will be 7.5 g and in sample 2 will be 16 g. b. three-fourths of each sample will have undergone radioactive decay. c. ten grams of each sample will have undergone radioactive decay. d. one-half of each sample will still be iodine-131.