Nuclear stability Knowledge-Based Download PDF

Questions

1. 1.

   Which statement best explains why the experimentally measured mass of a stable nucleus is always less than the sum of the masses of its constituent free protons and neutrons?

   • A) The missing mass is converted into orbital electrons that surround the newly formed nucleus.
   • B) The difference in mass corresponds to the nuclear binding energy released when the nucleons coalesce.
   • C) Protons lose a portion of their rest mass to neutralize electrostatic repulsion at close distances.
   • D) Neutrons shed mass in the form of neutrinos to achieve a stable, lower-energy quantum state.
2. 2.

   Which statement correctly explains the balance of fundamental forces that governs atomic nuclear stability?

   • A) Gravitational attraction between nucleons primarily counteracts the magnetic repulsion between aligned nuclear spins.
   • B) The weak nuclear force provides a long-range attractive pull between neutrons to balance the repulsive force of beta particles.
   • C) Electrostatic attraction between nuclear protons and surrounding electrons holds nucleons together against short-range repulsive strong forces.
   • D) The short-range attractive strong nuclear force between neighboring nucleons counteracts the long-range electrostatic repulsion between protons.
3. 3.

   When comparing the intrinsic stability of different atomic nuclei across the periodic table, which quantity serves as the most direct and reliable measure of nuclear stability?

   • A) Binding energy per nucleon
   • B) Total nuclear binding energy
   • C) Total nuclear mass defect
   • D) Total electrostatic potential energy of the protons
4. 4.

   Which of the following features is most directly associated with exceptional stability in atomic nuclei?

   • A) An odd number of protons combined with an odd number of neutrons
   • B) An atomic number greater than 83 paired with a 1:1 neutron-to-proton ratio
   • C) A closed nuclear shell containing a magic number of protons or neutrons, such as 2, 8, 20, 28, 50, 82, or 126
   • D) A binding energy per nucleon that is significantly lower than that of neighboring isobars
5. 5.

   Which statement correctly describes the relationship between the neutron-to-proton ($N/Z$) ratio and nuclear stability across the band of stability?

   • A) Stable light nuclei require an $N/Z$ ratio of approximately 1.5, whereas stable heavy nuclei require an $N/Z$ ratio of 1.0.
   • B) Nuclei containing an odd number of both protons and neutrons are consistently the most stable across the entire periodic table.
   • C) Electrostatic repulsion between protons diminishes as atomic number increases, reducing the need for stabilizing neutrons.
   • D) Stable light nuclei have an $N/Z$ ratio close to 1.0, whereas heavier stable nuclei require an $N/Z$ ratio closer to 1.5 to offset electrostatic repulsion between protons.