1. Chapter 4 Section 5: Radioactive Elements

2. Radioactivity The atomic nuclei of unstable isotopes (atoms with the same number of protons and different numbers of neutrons) release fast-moving particles of energy

3. Becquerel in 1896 discovered the effects of radioactive decay while studying uranium

4. Was named by the Curies (particles) Marie Curie was a physicist who spent her life studying radioactive materials.

5. Types Alpha: consists of 2 protons and 2 neutrons and is positively charged

6. The release of this type of radiation decreases the atomic number by 2 and the atomic mass by 4. (eg)Uranium-238 goes to Thorium-234

7. Beta: unstable atoms that have too many neutrons. During beta decay, a neutron becomes a negatively charged particle and a proton.

8. A beta particle is a fast-moving electron given off by the unstable nucleus, the new proton remains inside the nucleus. The nucleus then has one less neutron and one extra proton. Its mass number stays the same, but its atomic number increases by one.

9. Gamma: consists of high-energy waves, similar to X-rays. The rays have no charge and does not affect the atomic mass or number

10. Always accompanied by beta and alpha radiation

11. Effects of Nuclear Radiation: Alpha radiation is stopped by collisions with atoms. Will cause a bad burn to human skin

12. Beta particles are stopped by Aluminum 5 millimeters thick. Will damage human cells

13. Gamma rays need a piece of lead several centimeters thick or a meter thick wall of concrete to get stopped. Will pass through the human body destroying cells

14. Using Radioactive Isotopes Include tracing the steps of chemical reactions, industrial processes, and treating diseases

15. Radioactive isotopes signal where it is by emitting radiation that can be detected. (tracers)

16. Used to trace elements in plants, find weak spots in metal pipes, and detect medical problems and treat diseases