1. Chapter 7: Radiation

2. Remember from Chemistry: Mass numberMass number: the number of protons + number of neutrons Atomic numberAtomic number: the number of protons in an atom of an element. Isotopes:Isotopes: atoms of the same elements that have a different number of neutrons and therefore a different mass number

3. There are many isotopes of carbon. For example: carbon-12, carbon-13 and carbon-14 How many protons in each of these atoms of carbon? –6–6 How many neutrons in each of these atoms of carbon? Carbon-12 = ____ neutrons Carbon-13 = ____ neutrons Carbon-14 = ____ neutrons

4. Standard Atomic Notation Carbon-12 = 12 C 6 Carbon-13 = _____ Carbon-14 = _____ Mass number Atomic number

5. Isotopes of Hydrogen Hydrogen: 1 proton and 0 neutrons Deuterium: 1 proton and 1 neutron Tritium: 1 proton and 2 neutrons

6. Radioactive Decay: The nuclei of some isotopes are stable, whereas, others are not. In unstable nuclei, the nuclear force is not enough to overcome the repulsive electrical forces with in the nucleus. As a result the nuclei are radioactive. When an unstable nucleus emits radiation, it undergoes a radioactive decay

7. Types of radioactive decay Alpha Decay:Alpha Decay: Particle emitted: Helium nucleus Result: Atom with two fewer protons and neutrons Sample Equations: Parent isotope Daughter isotope U → _____ + He U → Th + _____

8. Types of radioactive decay BetaBeta Particle emitted: Electron Result: # of neutrons decrease by one and the # of protons increase by one = new element Sample Equations: Parent isotope Daughter isotope C → ____ + e C → N + ____

9. GammaGamma Particle emitted: No particle, but gives off excess energy Result: No change to type of nucleus, it just has less energy. Sample Equations: Parent isotope Daughter isotope Ba → _____ + Gamma radiation Ba → Ba + ______ Types of radioactive decay

10. On your data sheets: p12

11. Radiation

12. Assignment: Fill in the 7.1 worksheets p123-5 (all) and p126 (pick two alpha, two beta and two gamma questions) You are going to have to look up some of this information in your textbook Quiz next class –Identifying and completing decay equations –Given # of neutrons and number of protons can you determine, mass #, atomic #, the element, isotope name and isotope symbol.

13. Half Life Section 7.2 PLO: Unit 2 #5.2

14. Half Life: Half Life: The time required for half the nuclei of a sample of a radioactive isotope to decay. The half life is the same regardless of the starting amount of the isotope. Because the amount of all radioactive isotopes decrease by half in each half life, graphs that show the amounts of these isotopes at various times look similar. The only difference is the time scale for decrease.

15. Examples of half life:

16. Half Life Problems Figure out what the problem is asking you to find. Fill in the table with the information given to you in the problem.

17. Half Life Table for Solving Word Problems Time# of Half livesAmount of parent isotope ** optional ** Amount of daughter isotope 00 Original Amount 0 1 2 3 4

18. Homework: Fill in the 7.2 worksheets p134 (odd) and 135 For p 134 you must show the half life tables

19. Half Life Table for Solving Word Problems Time# of Half livesAmount of parent isotope ** optional ** Amount of daughter isotope 00 Original Amount 0 1 2 3 4