1. Nuclear Radiation Prentice-Hall Chapter 25.1 Dr. Yager

2. Objectives  Explain how an unstable nucleus releases energy.  Describe the three main types of nuclear radiation.

3. Marie Curie was a Polish scientist whose research led to a theory of radioactivity (a term she coined) and discovery of two radioactive elements, Radium and Polonium. She was the first woman to win a Nobel Prize and first person to win two Nobel Prizes, in physics and chemistry. In 1934 she died from leukemia caused by her long-term exposure to radiation. You will learn about the various types of radiation and their effects.

4. How does an unstable nucleus release energy? Marie Curie (1867-1934) and Pierre Curie (1859- 1906) were able to show that rays emitted by uranium, polonium and radium atoms found in pitchblende caused fogging in photographic plates and ionized surrounding air molecules. Marie Curie named the process by which materials give off such rays radioactivity. Marie Curie named the process by which materials give off such rays radioactivity. The penetrating rays and particles emitted by a radioactive source are called radiation. The penetrating rays and particles emitted by a radioactive source are called radiation.

5. Nuclear reactions differ from chemical reactions in several important ways. In chemical reactions, atoms tend to attain stable electron configurations by losing or sharing electrons. In chemical reactions, atoms tend to attain stable electron configurations by losing or sharing electrons. In nuclear reactions, the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing nuclear changes. In nuclear reactions, the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing nuclear changes.

6. An unstable nucleus releases energy by emitting radiation during the process of radioactive decay. Key Concept:

7. The three main types of nuclear radiation are alpha radiation, beta radiation, and gamma radiation.

8. Alpha Radiation Alpha radiation consists of helium nuclei that have been emitted from the nucleus. These emitted particles, called alpha particles, contain two protons and two neutrons and have a double positive charge.

10. Beta Radiation Beta radiation consists of an electron resulting from the breaking apart of a neutron in an atom.

12. Example: β- radiation Carbon-14 emits a beta particle as it undergoes radioactive decay to form nitrogen-14. Carbon-14 emits a beta particle as it undergoes radioactive decay to form nitrogen-14.

13. Gamma Radiation Gamma radiation consists of high-energy photons emitted by a nucleus of a radioisotope. The high- energy photons are electromagnetic radiation.

14. Penetrating Ability of Radiation

16. 1.Certain elements are radioactive because their atoms have because their atoms have A. more neutrons than electrons. B. an unstable nucleus. C. a large nucleus. D. more neutrons than protons.

17. 1.Certain elements are radioactive because their atoms have because their atoms have A. more neutrons than electrons. B. an unstable nucleus. C. a large nucleus. D. more neutrons than protons.

18. 2. An unstable nucleus releases energy by energy by A. emitting radiation. B. thermal vibrations. C. a chemical reaction. D. giving off heat.

19. 2. An unstable nucleus releases energy by energy by A. emitting radiation. B. thermal vibrations. C. a chemical reaction. D. giving off heat.

20. 3.Which property does NOT describe an alpha particle? describe an alpha particle? A. 2+ charge B. a relatively large mass C. a negative charge D. low penetrating power

21. 3.Which property does NOT describe an alpha particle? describe an alpha particle? A. 2+ charge B. a relatively large mass C. a negative charge D. low penetrating power

22. 4.When a radioactive nucleus releases a high-speed electron, the process can be described as A. oxidation. B. alpha emission. C. beta emission. D. gamma radiation.

23. 4.When a radioactive nucleus releases a high-speed electron, the process can be described as A. oxidation. B. alpha emission. C. beta emission. D. gamma radiation.

24. 5. What form of radiation has the highest penetrating power? A. oxidation. B. alpha emission. C. beta emission. D. gamma radiation.

25. 5. What form of radiation has the highest penetrating power? A. oxidation. B. alpha emission. C. beta emission. D. gamma radiation.