Author Question: The isotope 238U, which starts one of the natural radioactive series, decays first by alpha decay ... (Read 68 times)

urbanoutfitters · **on:** Jul 28, 2018

The isotope 238U, which starts one of the natural radioactive series, decays first by alpha decay followed by two negative beta decays. At this point, what is the resulting isotope?
a. 234Th (Z = 90 for Th.)
b. 236U
c. 238U
d. Some other uranium isotope not given above.

Question 2

In the four radioactive series, the nuclei decay by either emitting alpha particles or beta particles until they reach the stable end product. Each decay, therefore, results in a mass number change of either 4 (for alpha decay) or 0 (for beta decay). The radium isotope 226Ra is in one of these series. What is the starting isotope in the series containing 226Ra?
a. 238U
c. 232Th
b. 235U
d. 237Np