Nuclear stability Knowledge-Based Practice

Questions

1. 1.

   Which statement best explains why binding energy per nucleon, rather than total binding energy, is used to compare the relative stability of different atomic nuclei?

   • A) Total binding energy decreases as mass number increases, causing larger nuclei to appear erroneously unstable.
   • B) Total binding energy accounts only for proton-proton repulsions, whereas binding energy per nucleon includes neutron interactions.
   • C) Total binding energy generally increases with the total number of nucleons, so dividing by the mass number reflects how tightly each nucleon is held on average.
   • D) Total binding energy fluctuates with chemical bonding states, whereas binding energy per nucleon is an intrinsic nuclear constant.
2. 2.

   Which statement best explains the balance of fundamental forces responsible for maintaining the stability of an atomic nucleus?

   • A) The long-range gravitational attraction between nucleons overcomes the electrostatic repulsion among protons.
   • B) The repulsive weak nuclear force is neutralized by the attractive magnetic dipole interactions of neutrons.
   • C) The attractive, short-range strong nuclear force overcomes the electrostatic repulsion between positively charged protons.
   • D) The electrostatic attraction between protons and neutrons completely counteracts the repulsive effect of the strong nuclear force.
3. 3.

   In nuclear chemistry, certain nucleon numbers correspond to completely filled nuclear energy shells and confer exceptional stability to an atomic nucleus. Which pair of numbers consists entirely of these nuclear magic numbers?

   • A) 10 and 18
   • B) 28 and 82
   • C) 36 and 54
   • D) 40 and 70
4. 4.

   Which combination of protons and neutrons characterizes the vast majority of stable, naturally occurring nuclides?

   • A) An odd number of protons and an odd number of neutrons
   • B) An odd number of protons and an even number of neutrons
   • C) An even number of protons and an even number of neutrons
   • D) An even number of protons and an odd number of neutrons
5. 5.

   How does the neutron-to-proton ratio ($N/Z$) of stable nuclides change as the atomic number increases along the band of stability?

   • A) It remains constant at approximately 1.0 across all stable elements up to bismuth.
   • B) It increases from approximately 1.0 for light nuclei to about 1.5 for heavy nuclei.
   • C) It decreases from about 1.5 for light nuclei to approximately 1.0 for heavy nuclei.
   • D) It fluctuates randomly regardless of the total number of protons present in the nucleus.

Answers and step-by-step solutions appear after you finish the test.