1. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 1 Chapter 16 Nuclear Radiation 16.1 Natural Radioactivity A person working with radioisotopes wears protective clothing and gloves and stands behind a shield.

2. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 2 Radioactive Isotopes A radioactive isotope has an unstable nucleus emits radiation to become more stable can be one or more isotopes of an element is written with a mass number and an atomic number includes the mass number in its name Example: iodine-131

3. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 3 Examples of Radioactive Isotopes

4. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 4 Learning Check Thallium-201 is used for heart scans to determine cardiac function. A. How many protons are in thallium-201? B. How many neutrons are in thallium-201? C. What is the atomic symbol of thallium-201?

5. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 5 Solution Thallium-201 is used for heart scans to determine cardiac function. A. How many protons are in thallium-201? Thallium, symbol Tl, has 81 protons. B. How many neutrons are in thallium-201? mass number 201  atomic number 81 = 120 neutrons C. What is the atomic symbol of thallium-201? mass number 201 Tl atomic number 81

6. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 6 Nuclear Radiation Nuclear radiation is the radiation emitted by an unstable atom takes the form of alpha particles, neutrons, beta particles, positrons, or gamma rays

7. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 7 Alpha Particle An alpha (  ) particle has a helium nucleus 2 protons and 2 neutrons a mass number of 4 a charge of 2+ a low energy compared to other radiation particles

8. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 8 Beta Particle A beta (  ) particle is a high-energy electron has a mass number of 0 has a charge of 1- forms in an unstable nucleus when a neutron changes into a proton and an electron

9. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 9 Positron A positron (  + ) has a mass number of 0 has a charge of 1+ forms in an unstable nucleus when a proton changes into a neutron and a positron

10. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 10 Gamma (  ) Ray A gamma (  ) ray is high-energy radiation has a mass number of 0 has a charge of 0 is emitted from an unstable nucleus to give a more stable, lower energy nucleus

11. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 11 Summary of Common Forms of Nuclear Radiation

12. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 12 Learning Check Give the mass number and charge of each type of radiation. 1. alpha particle 2. positron 3. beta particle 4. neutron 5. gamma ray

13. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 13 Solution Mass Number Charge 1. alpha particle 42+ 2. positron01+ 3. beta particle01- 4. neutron10 5. gamma ray00

14. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 14 Radiation protection requires paper and clothing for alpha particles a lab coat or gloves for beta particles a lead shield or a thick concrete wall for gamma rays limiting the amount of time spent near a radioactive source increasing the distance from the source Radiation Protection

15. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 15 Radiation and Shielding Required

16. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 16 Radiation Protection Different types of shielding are needed for different radiation particles.

17. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 17 Learning Check Indicate the type of radiation (alpha, beta, and/or gamma) protection for each type of shielding. 1) heavy clothing 2) paper 3) lead 4) lab coat 5) thick concrete A person working with radioisotopes wears protective clothing and gloves and stands behind a shield.

18. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 18 Solution Indicate the type of radiation (alpha, beta, and/or gamma) protection for each type of shielding. 1) heavy clothingalpha, beta 2) paperalpha 3) leadalpha, beta, gamma 4) lab coat alpha, beta 5) thick concrete alpha, beta, gamma