The document discusses nuclear physics and radioactivity. It describes the structure of atomic nuclei consisting of protons and neutrons. Isotopes are nuclei that contain the same number of protons but different neutrons. The strong nuclear force holds the nucleus together by counteracting the repulsive force between protons. As nuclei get larger, more neutrons are required for stability. Nuclear binding energy is released when nuclei fuse because the actual mass is less than the sum of the individual parts. There are three types of particles, alpha, beta, and gamma, emitted during radioactive decay as nuclei move to more stable configurations.

1. Chapter 31 Nuclear Physics and Radioactivity

2. 31.1 Nuclear Structure The atomic nucleus consists of positively charged protons and neutral neutrons.

3. 31.1 Nuclear Structure atomic number atomic mass number

4. 31.1 Nuclear Structure Nuclei that contain the same number of protons but a different number of neutrons are known as isotopes .

5. 31.1 Nuclear Structure

6. 31.2 The Strong Nuclear Force and the Stability of the Nucleus The mutual repulsion of the protons tends to push the nucleus apart. What then, holds the nucleus together? The strong nuclear force.

7. 31.2 The Strong Nuclear Force and the Stability of the Nucleus As nuclei get larger, more neutrons are required for stability. The neutrons act like glue without adding more repulsive force.

8. 31.3 The Mass Deficit of the Nucleus and Nuclear Binding Energy

9. 31.3 The Mass Deficit of the Nucleus and Nuclear Binding Energy Example 3 The Binding Energy of the Helium Nucleus Revisited The atomic mass of helium is 4.0026u and the atomic mass of hydrogen is 1.0078u. Using atomic mass units, instead of kilograms, obtain the binding energy of the helium nucleus.

10. 31.3 The Mass Deficit of the Nucleus and Nuclear Binding Energy

11. 31.3 The Mass Deficit of the Nucleus and Nuclear Binding Energy

12. 31.4 Radioactivity A magnetic field separates three types of particles emitted by radioactive nuclei.

13. 31.4 Radioactivity α DECAY

14. 31.4 Radioactivity A smoke detector

15. 31.4 Radioactivity β DECAY

16. 31.4 Radioactivity γ DECAY excited energy state lower energy state