Chapter 22: Nuclear Chemistry

Nucleus

The dense core of an atom that contains protons and neutrons.

Nucleons

Particles in the nucleus, including protons and neutrons.

Radioisotope

An isotope with an unstable nucleus that emits radiation to reach stability.

Mass Defect

The difference between the calculated mass of nucleons and the actual mass of the nucleus.

Nuclear Binding Energy

The energy required to hold the nucleus together, derived from the mass defect using Einstein's equation \(E = mc^2\).

Nuclear Stability

• Determined by the neutron-to-proton ratio.
• Small nuclei are stable with a 1:1 ratio of neutrons to protons.
• Larger nuclei require a higher neutron-to-proton ratio to remain stable.
• The band of stability shows the relationship between the number of neutrons and protons in stable nuclei.

Nuclear Shell Model

• Nucleons occupy energy levels or shells within the nucleus.
• Magic numbers of protons or neutrons (e.g., 2, 8, 20, 28, 50, 82) correspond to highly stable configurations.
• Explains the enhanced stability of specific isotopes.

Measuring Radiation

Becquerel (Bq)

The SI unit of radioactivity, representing one decay per second.

Gray (Gy)

The SI unit for the absorbed dose of radiation, representing energy per kilogram of matter.

Sievert (Sv)

The SI unit that measures the biological effect of radiation, accounting for its type and energy.

Questions for Students

1. Define nucleons and explain their role in the nucleus.
2. What is the mass defect, and how is it related to nuclear binding energy?
3. How does the neutron-to-proton ratio affect nuclear stability?
4. Explain the concept of magic numbers in the nuclear shell model.
5. What are the differences between the units Becquerel, Gray, and Sievert?