1. 1 Nuclear Radiation

2. 2 Radiation Radiation comes from the nucleus of an atom. Unstable nucleus emits a particle or energy  alpha  beta  gamma

3. 3 Alpha Particle Same as a helium nucleus 4 2 He or  Two protons Two neutrons Mass number Atomic number

4. 4 Beta Particle  An electron emitted from the nucleus 0 e or   1 A neutron in the nucleus breaks down 11 0 n H +e 0 +1 -1

5. Positron Particle The antiparticle counterpart to the electron Has an electric charge of +1 5 0e0e +1 00 or positron

6. 6 Gamma Radiation  Pure radiation Like an X-ray but comes from the nucleus

7. 7 Radiation Protection Shielding alpha – paper, clothing beta – lab coat, gloves gamma- lead, thick concrete

8. 8 Radiation Protection

9. 9 Balancing Nuclear Equations In the reactants and products Atomic numbers must balance and Mass numbers must balance

10. 10 Alpha decay

11. 11 Beta decay 234 Th  234 Pa + 0 e 90 91  1 beta particle

12. 12 Gamma radiation No change in atomic or mass number 11 B 11 B + 0  5 5 0 boron atom in a high-energy state

13. 13 Learning Check Write the nuclear equation for the beta decay of Co-60.

14. 14 Solution Write the nuclear equation for the Beta decay of Co-60. 60 Co 60 Ni + 0 e 27 28 -1

15. 15 Producing Radioactive Isotopes Bombardment of atoms produces radioisotopes = 60 = 60 59 Co + 1 n 56 Mn + 4 H e 27 0 25 2 = 27= 27 cobalt neutron manganese alpha atom radioisotope particle

16. 16 Learning Check What radioactive isotope is produced in the following bombardment of boron? 10 B + 4 He ? + 1 n 5 2 0

17. 17 Solution What radioactive isotope is produced in the following bombardment of boron? 10 B + 4 He 13 N + 1 n 5 2 7 0 nitrogen radioisotope

18. 18 Half-Life of a Radioisotope The time for the radiation level to fall (decay) to one-half its initial value decay curve 8 mg 4 mg2 mg 1 mg initial 1 half-life 2 3

19. 19 Examples of Half-Life Isotope Half life C-152.4 sec Ra-2243.6 days Ra-22312 days I-12560 days C-145700 years U-235710 000 000 years

20. 20 Learning Check The half life of I-123 is 13 hr. How much of a 64 mg sample of I-123 is left after 26 hours?

21. 21 Solution t 1/2 =13 hrs 26 hours = 2 x t 1/2 Amount initial =64mg Amount remaining = 64 mg x ½ x ½ = 16 mg

22. 22 Nuclear Fission Fission large nuclei break up 235 U + 1 n 139 Ba + 94 Kr + 3 1 n + 92 0 56 36 0 Energy

23. 23 Fission

24. 24 Nuclear Fusion Fusion small nuclei combine 2 H + 3 H 4 He + 1 n + 1 1 2 0 Occurs in the sun and other stars Energy

25. 25 Learning Check Indicate if each of the following are (1)Fission(2) fusion A.Nucleus splits B.Large amounts of energy released C.Small nuclei form larger nuclei D.Hydrogen nuclei react Energy

26. 26 Solution Indicate if each of the following are (1)Fission(2) fusion A. 1 Nucleus splits B. 1 + 2 Large amounts of energy released C. 2 Small nuclei form larger nuclei D. 2 Hydrogen nuclei react