Radioactive decay series Knowledge-Based Download PDF

Questions

1. 1.

   In a natural radioactive decay series, when the parent radionuclide possesses a half-life that is vastly longer than that of any intermediate daughter nuclide, a steady state is eventually established where the activity of each daughter equals the activity of the parent. What term describes this specific type of radioactive equilibrium?

   • A) Transient equilibrium
   • B) Secular equilibrium
   • C) Dynamic chemical equilibrium
   • D) Radiative thermal equilibrium
2. 2.

   Which primordial radionuclide serves as the long-lived parent isotope that initiates the natural actinium ($4n + 3$) decay series?

   • A) Thorium-232
   • B) Uranium-238
   • C) Uranium-235
   • D) Neptunium-237
3. 3.

   Radioactive decay series are classified by the mathematical form of the mass numbers of their member nuclides. Which radioactive decay series is characterized by nuclides whose mass numbers satisfy the expression $A = 4n + 2$ and terminates at the stable nuclide lead-206?

   • A) Thorium series
   • B) Actinium series
   • C) Uranium series
   • D) Neptunium series
4. 4.

   Which heavy radioactive decay series is absent from nature because its parent nuclide has a relatively short half-life compared to the age of the Earth, terminating at bismuth-209 instead of a stable lead isotope?

   • A) Thorium series
   • B) Actinium series
   • C) Uranium series
   • D) Neptunium series
5. 5.

   In the natural radioactive thorium decay series, a parent nucleus of thorium-232 ($^{232}_{90}\text{Th}$) undergoes a succession of decays to form a stable daughter nucleus of lead-208 ($^{208}_{82}\text{Pb}$). How many alpha particles and beta-minus particles are emitted in total during this entire decay chain?

   • A) 4 alpha particles and 6 beta-minus particles
   • B) 6 alpha particles and 6 beta-minus particles
   • C) 6 alpha particles and 4 beta-minus particles
   • D) 8 alpha particles and 4 beta-minus particles