1. HomeworkHomework Read section 4.4 Answer questions 26 & 27 on page 107.

2. What you will learn today:

4. nuclear reaction radioactive decay alpha particle beta particle gamma ray

5. Chemistry is all about the electrons.

6. The nucleus doesn’t get involved in chemical reactions.

7. But there are such things as nuclear reactions.

8. In the late 1800’s, scientists discovered radioactivity.

18. So what is radioactivity? In the late 1800’s, scientists discovered radioactivity.

19. Radioactive source in a lead box screen So what is radioactivity?

20. positive negative screen So what is radioactivity?

21. positive negative So what is radioactivity?

22. Alpha (α) +2 positive negative So what is radioactivity?

23. Alpha (α) +2 positive negative So what is radioactivity?

24. Alpha (α) +2 positive negative Beta (β) So what is radioactivity?

25. Alpha (α) +2 positive negative Beta (β) So what is radioactivity?

26. Alpha (α) +2 positive negative Beta (β) Gamma (γ) 0 So what is radioactivity?

27. alpha particle α 2 protons + 2 neutrons mass ≈ 4 AMU charge = +2 So what is radioactivity?

28. beta particle β 1 electron mass ≈ 1 / 1000 AMU charge = -1 So what is radioactivity?

29. gamma ray γ pure energy mass = 0 charge = 0 So what is radioactivity?

30. 226 88 Ra So what is radioactivity?

31. mass number 226 atomic number 88 Ra So what is radioactivity?

32. 226 88 Ra → So what is radioactivity?

33. 226 222 88 86 Ra → Rn So what is radioactivity?

34. 226 222 4 88 86 2 Ra → Rn + He So what is radioactivity?

35. 226 222 4 88 86 2 Ra → Rn + He radium-226 So what is radioactivity?

36. 226 222 4 88 86 2 Ra → Rn + He radium-226 radon-222 So what is radioactivity?

37. 226 222 4 88 86 2 Ra → Rn + He radium-226 radon-222 alpha particle So what is radioactivity?

38. radium-226 radon-222 alpha particle So what is radioactivity?

39. 238 234 4 0 92 90 2 0 U→U→ Th + He + 2 γ So what is radioactivity?

40. 238 234 4 0 92 90 2 0 U→U→ Th + He + 2 uranium-238 thorium-234 alpha particle gamma ray γ So what is radioactivity?

41. uranium-238 thorium-234 alpha particle gamma ray So what is radioactivity?

42. 14 14 0 6 7 -1 C→C→ N + β So what is radioactivity?

43. 14 14 0 6 7 -1 C→C→ N + β carbon-14 nitrogen-14 beta particle So what is radioactivity?

47. HomeworkHomework Read section 4.4 Answer questions 26 & 27 on page 107.