Question-

1. Argon-37 decays via electron capture emission, which equation represents the balanced nuclear equation?

a) 18Ar37 à -1e0 + 17Cl37

b) 18Ar37 + -1e0 à 17Cl37

c) 18Ar37 + 1e0 à 17Cl37

d) 18Ar37 + -1e0 à 16S37

e) None of the above

2. 131I decays with a t1/2 = 8.07 hrs. If we begin with 3.0 mg, how much remains after 6 half-lives?

a) 0.0469 mg

b) 0.0234 mg

c) 0.50 mg

d) 0.25 mg

e) 0.01875

3. The half-life of Pa-234 is 6.75 hr. Approximately what fraction of a sample of isotope remains after 20.25 hours?

a) 1/4

b) 1/8

c) 1/16

d) 1/3

e) 1/2