1. 1 Nuclear Chemistry Active Chemistry

2. 2 Review Atomic Notation

3. 3 Nucleons Protons and Neutrons The nucleons are bound together by the strong force. Nucleons are made of Quarks which are considered to be fundamental particles. Quarks bind together with gluons to make composite particles called hadrons. The most common examples of a hadron are neutrons and protons.

4. 4 Isotopes Atoms of a given element with: same #protons but different # neutrons

5. 5 Isotopes of Carbon

6. 6 Isotopes of certain unstable elements that spontaneously emit particles and energy from the nucleus. Henri Beckerel 1896 accidentally observed radioactivity of uranium salts that were fogging photographic film. His associates were Marie and Pierre Curie. Radioactive Isotopes

7. 7 1876-1934 Marie Curie: 1876-1934 born in Poland Lived in France 1898 discovered the elements polonium and radium. She discovered radioactivity, the spontaneous disintegration of some elements into smaller pieces.She discovered radioactivity, the spontaneous disintegration of some elements into smaller pieces. Winner of 1903 Nobel Prize for Physics with Henri Becquerel and her husband, Pierre Curie. Winner of the sole 1911 Nobel Prize for Chemistry. She died of aplastic anaemia, a blood disease that often results from exposure to large amounts of radiation.

8. 8 Nuclear Reactions vs. Normal Chemical Changes Nuclear reactions involve the nucleusNuclear reactions involve the nucleus The nucleus opens, and protons and neutrons are rearrangedThe nucleus opens, and protons and neutrons are rearranged The opening of the nucleus releases a tremendous amount of energy that holds the nucleus together – called binding energyThe opening of the nucleus releases a tremendous amount of energy that holds the nucleus together – called binding energy “Normal” Chemical Reactions involve electrons, not protons and neutrons“Normal” Chemical Reactions involve electrons, not protons and neutrons

9. 9 Types of Radiation Alpha (  ) – a positively charged (+2) helium isotope we usually ignore the charge because it involves electrons, not protons and neutrons Alpha (  ) – a positively charged (+2) helium isotope we usually ignore the charge because it involves electrons, not protons and neutrons Beta (β) – an electronBeta (β) – an electron Gamma (γ) – pure energy; called a ray rather than a particleGamma (γ) – pure energy; called a ray rather than a particle

10. 10 Other Nuclear Particles Neutron Neutron Positron – a positive electron Positron – a positive electron Proton – usually referred to as hydrogen-1Proton – usually referred to as hydrogen-1 Any other elemental isotopeAny other elemental isotope

11. 11 Sheilding Ability ChemSaver p. 20

12. 12 X A Z Mass Number Atomic Number Element Symbol Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutrons A Z 1p1p 1 1H1H 1 or proton 1n1n 0 neutron 0e0e 00 or Beta 0e0e +1 00 or positron 4 He 2 44 2 or  particle 1 1 1 0 0 0 +1 4 2 ChemSaver p. 20

13. 13 Balancing Nuclear Equations 1.Conserve mass number (A). The sum of protons plus neutrons in the products must equal the sum of protons plus neutrons in the reactants. 1n1n 0 U 235 92 + Cs 138 55 Rb 96 37 1n1n 0 ++ 2 235 + 1 = 138 + 96 + 2x1 2.Conserve atomic number (Z) or nuclear charge. The sum of nuclear charges in the products must equal the sum of nuclear charges in the reactants. 1n1n 0 U 235 92 + Cs 138 55 Rb 96 37 1n1n 0 ++ 2 92 + 0 = 55 + 37 + 2x0 23.1

14. 14 Emission of alpha particles  : helium nuclei two protons and two neutrons charge +2 can travel a few inches through air can be stopped by a sheet of paper, clothing. Alpha Decay 4 He 2 44 2 or  particle

15. 15 Alpha Decay Uranium Thorium

16. 16 Beta Decay Beta particles  : electrons ejected from the nucleus when neutrons decay n  p + +  - Beta particles have the same charge and mass as "normal" electrons. 0e0e 00 or Beta

17. 17 Beta Decay Thorium Protactinium

18. 18 Gamma Decay Gamma radiation  electromagnetic energy that is released. Gamma rays are electromagnetic waves. They have no mass. Gamma radiation has no charge. –Most Penetrating, can be stopped by 1m thick concrete or a several cm thick sheet of lead.

19. 19 Transmutation Transmutation, or artificial radioactivity, is when you hit a nucleus with a projectile. If the projectile hits the nucleus at a great enough rate, the projectile and the nucleus will fuse together and make a larger nucleus. In most cases, the nucleus will eject a by-product particle.

20. 20 Tranmutation The target nucleus is the isotope which is bombarded (in the example above, the lead-207) The projectile is the particle fired at the nucleus (carbon-12) The product is the new nucleus produced by the reaction (francium-218) The ejected particle is the light nucleus or particle emitted in the reaction (hydrogen-1)

21. 21 Example: What is the product nucleus when a uranium- 235 nucleus is hit with a hydrogen-2 nucleus, and a neutron is ejected from the target?

22. 22 By the law of conservation of matter, the product side of the reaction should add up to the reactant side in terms of the atomic number.

23. 23 Learning Check What radioactive isotope is produced in the following bombardment of boron? 10 B + 4 He ? + 1 n 5 2 0

24. 24 Learning Check What radioactive isotope is produced in the following bombardment of boron? 10 B + 4 He 13 N + 1 n 5 2 7 0

25. 25 Write Nuclear Equations! Write the nuclear equation for the beta emitter Co-60. 60 Co 0 e+ 60 Ni 27 -128

26. 26

27. 27 Nuclear Fission

28. 28 Nuclear Fission Fission is the splitting of atoms These are usually very large, so that they are not as stable ChemSaver p. 20

29. 29 Representation of a fission process.

30. 30 Nuclear Fission & POWER Currently about 103 nuclear power plants in the U.S. and about 435 worldwide.Currently about 103 nuclear power plants in the U.S. and about 435 worldwide. 17% of the world’s energy comes from nuclear.17% of the world’s energy comes from nuclear.

31. 31 Figure 19.6: Diagram of a nuclear power plant.

32. 32 Nuclear Fusion Fusion nuclei combine to form a more massive nucleus 2 H + 3 H 4 He + 1 n + 1 1 2 0 Occurs in the sun and other stars Energy ChemSaver p. 20