1. Chapter Preview 4.1 Introduction to Atoms 4.2 Organizing the Elements 4.3 Metals 4.4 Nonmetals, Inert Gases, and Semimetals 4.5 Radioactive Elements Table of Contents Chapter Preview 4.1 Introduction to Atoms 4.2 Organizing the Elements 4.3 Metals 4.4 Nonmetals, Inert Gases, and Semimetals 4.5 Radioactive Elements

2. Section 5: Radioactive Elements How was radioactivity discovered?

3. Section 5: Radioactive Elements How was radioactivity discovered? In 1896, the French scientist Henri Becquerel discovered the effects of radioactive decay by accident while studying a mineral containing uranium.

4. Section 5: Radioactive Elements What types of particles and energy can radioactive decay produce?

5. Section 5: Radioactive Elements What types of particles and energy can radioactive decay produce? Radioactive decay can produce alpha particles, beta particles, and gamma rays.

6. Types of Radioactive Decay During alpha decay, a nucleus loses an alpha particle, which consists of two protons and two neutrons.

7. Types of Radioactive Decay During beta decay, a neutron inside an unstable nucleus changes into a negatively charged beta particle and a proton.

8. Types of Radioactive Decay Gamma radiation has no charge and does not cause a change in either the atomic mass or the atomic number.

9. Types of Radioactive Decay The three types of nuclear radiation were named based on how easily each one could be blocked. Alpha, beta, and gamma are the first three letters of the Greek alphabet.

10. Section 5: Radioactive Elements In what ways are radioactive isotopes useful?

11. Section 5: Radioactive Elements In what ways are radioactive isotopes useful? Uses of radioactive isotopes include tracing the steps of chemical reactions and industrial processes, and diagnosing and treating disease

12. Using Radioactive Isotopes Tracers are radioactive isotopes that can be followed through the steps of a chemical reaction or industrial process.

13. Radioactive Tracers Activity Click the Active Art button to open a browser window and access Active Art about radioactive tracers.

14. Radiation Click the Video button to watch a movie about radiation.

15. End of Section: Radioactive Elements

16. Citations http://www.scientific- web.com/en/Physics/Biographies/images/HenriBecqu erel.jpg http://www.scientific- web.com/en/Physics/Biographies/images/HenriBecqu erel.jpg http://www.freedomforfission.org.uk/img/emission.j pg http://www.freedomforfission.org.uk/img/emission.j pg