2. Why are some elements (isotopes) more stable than others?

3. The Nucleus The Electric Force

4. Protons hate Protons Strong Force

5. Strong Force Facts Neutrons act like cement Strong Force is very strong over a small distance (about the distance of two protons) Small elements, 1 proton to 1 neutron will do

6. Large Elements http://www.ptable.com/

7. Thorium (Th)Protactinium (Pa) Beta Particle

8. Protactinium (Pa) Alpha Particle Actinium (Ac)

9. Beta & Alpha RadiationGamma Radiation

10. Quick Quiz What is the difference between the electric force and the strong force? What are the three types of radiation that are present in radioactive decay?

11. Example Uranium 238

12. How can radioactive decay be useful? Dating

13. The time it takes for half of the original quantity to decay The half-life of an element is constant, and not affected by external conditions

14. Iodine-131 decays to Xenon-131 Day: Half-life: 8 days 18 Number of Iodine: Xenon: 16 0 8 8 12 4 24 2 14 32 1 15 40 0 16

15. Radiometric Dating (isotopic dating) Organic: Radiocarbon dating Range: 50,000 years Carbon in atmosphere not constant Inorganic: Uranium to Lead dating Range: 7 million to 4.5 billion years

16. Quick Quiz 2 What is half-life? Is radiocarbon dating extremely accurate, why or why not?

17. Radiation is dangerous!

18. How do they measure radiation! Geiger counter Rad a unit of absorbed radiation dose 1 rad = 10 mj Rem amount of biological damage due to radiation dose 1000 rem or higher will be fatal

19. Radiatonradrem Gamma11 X-Ray11 Beta particle11 Alpha particle120 Table of rad vs rem