1. What Would You See if you Were On a Nucleus?

2. Topics for Today Elements and Atoms and Molecules, oh boy Inside the Atom Mass Number and Isotopes More on Radon

3. Readings in Text 1.7 Atoms & Molecules 2.2 Atomic Structure and Periodicity

4. Topics for Friday Quiz #1 at the end of the period. You can find the practice questions on the course website (News of the Week on the Monthly Calender).

5. What is radiation? How do radioactive substances behave?

6. Topics for Friday Radiation History and discovery of radioactivity Alpha, beta, and gamma decay Quiz #1

7. Readings Chapter 2 on the electromagnetic spectrum (page 75) Chapter 7.7 - What is radioactivity? How are gamma rays different than visible light? How are they similar?

8. Announcements Assignment #1 is due in your TA’s email Inbox Monday before lecture! Please send to your TA and myself! See the course website for the full details!

9. PRELAB QUIZ for Week #2 Due before your lab next week Unlimited number of tries allowed this week only.

10. Topics for Today Elements and Atoms and Molecules, oh boy Inside the Atom Mass Number and Isotopes More on Radon

11. Handout

12. ELEMENT: Eleven elements make up over 99% of your body. Which ones?

13. Which compound is most abundant in your body? Chapter 11 (page 488) Elements in the human body Figure 11.3 and Table 11.2

14. Review - Elements One of the hundred or so symbols on the periodic table. Which ones do you need to know? Rn 86

15. Interlude

16. An atom is the smallest particle of an element that we can identify as the element. Can we SEE atoms?

17. Microscopes

18. Copper Surface Scanning Tunneling Microscope

19. What is wrong with this picture?

20. How big are these atoms?

21. Short Answer The diameter is around 1 to 5 x 10 -10 meters Or 0.0000000001 meters! How small is this?

22. Powers of 10 Website http://molecular.magnet.fsu.edu/primer/jav a/scienceopticsu/powersof10/index.html

23. A pinhead is about 1 x 10 -3 meters (1 mm) in diameter Therefore, more than 1,000,000 atoms can fit across a pinhead!

24. ~3 x 10 -10 meters in diameter (~300 x 10 -12 meter)

25. ~3 x 10 -10 meter The nucleus is about 1/100,000 of the diameter.

26. Back to the Pinheads What if the nucleus had a diameter of a pinhead (1 mm)?

27. Back to the Pinheads What if the nucleus had a diameter of a pinhead (1 mm)? How big would the atom be?

28. Back to the Pinheads What if the nucleus had a diameter of a pinhead (1 mm)? How big would the atom be? 10 meters!

29. 10 cm If the nucleus were 10 cm in diameter, then… the edge of the atom would be 1,000,000 cm or 10,000 meters or 6 miles away!

30. 10 cm If the nucleus were 10 cm in diameter, then… the edge of the atom would be 1,000,000 cm or 10,000 meters or 6 miles away! SO, what would you see if you were on the nucleus?

32. A whole lot of empty space…

33. What is in an atom?

34. Proton + in nucleus ~1 Neutron neutral in nucleus ~1 Electron – outside nucleus ~0 Charge Location Mass

35. Proton + in nucleus ~1 Neutron neutral in nucleus ~1 Electron – outside nucleus ~0 Charge Location Mass Where is the mass located?

36. Proton + in nucleus ~1 Neutron neutral in nucleus ~1 Electron – outside nucleus ~0 Charge Location Mass What gives an atom its volume?

37. Back to Radon… Atomic Number (protons), Z

38. How else can we write this? X AZAZ X = Element Symbol from periodic table A = Mass number (protons + neutrons) Z = Number of Protons

39. How else can we write this? X AZAZ X = Element Symbol from periodic table A = Mass number (protons + neutrons) Z = Number of Protons Try this for radon- 222!

40. Rn radon-222 222 86

41. For the quiz… Calculators are OK. Cannot use any calculators with memory!

42. Quiz Cont… Please sit ONLY in the ‘dark’ colored seats!

43. Back to the Atom…

44. Rn radon-222 222 86 Is this needed?

45. Rn 222 Rn radon-222 222 86 How about this?

46. Rn Rn Rn Rn 224 86 223 86 222 86 221 86 220 86 219 86 218 86 217 86 216 86 215 86 214 86 213 86 212 86 211 86 210 86 209 86 208 86 207 86 206 86 205 86

47. Rn Rn Rn Rn 224 86 223 86 222 86 221 86 220 86 219 86 218 86 217 86 216 86 215 86 214 86 213 86 212 86 211 86 210 86 209 86 208 86 207 86 206 86 205 86 These are the _______ of radon.

48. Rn Rn Rn Rn 224 86 223 86 222 86 221 86 220 86 219 86 218 86 217 86 216 86 215 86 214 86 213 86 212 86 211 86 210 86 209 86 208 86 207 86 206 86 205 86 These are the isotopes of radon.

49. Rn Rn Rn Rn 224 86 223 86 222 86 221 86 220 86 219 86 218 86 217 86 216 86 215 86 214 86 213 86 212 86 211 86 210 86 209 86 208 86 207 86 206 86 205 86 What do these isotopes have in common? How do they differ?

50. All the atoms of an element have the same number of ___________, … but the isotopes of an element differ in the number of ___________.

51. Remember This!! All the atoms of an element have the same number of protons, … but the isotopes of an element differ in the number of neutrons.

52. What does it mean to be “Stable?”

53. There are two definitions of stable…

54. What does it mean to be “Stable?” 1.Chemically Stable – Generally unreactive (noble gases) 2.Stable with respect to their nucleus – NOT radioactive.

55. What does it mean to be “Stable?” 1.Chemically Stable – Generally unreactive (noble gases) 2.Stable with respect to their nucleus – NOT radioactive. Radioactive substances are said to be “unstable”

56. What does it mean to be “Stable?” 1.Chemically Stable – Generally unreactive (noble gases) 2.Stable with respect to their nucleus – NOT radioactive. Radioactive substances are said to be “unstable” Back to isotopes!

57. All the atoms of an element have the same number of protons, … but the isotopes of an element differ in the number of neutrons. How else are the isotopes similar?

58. 2 H 2 + O 2 2 H 2 O All the isotopes react in the same way.

59. 2 H 2 + O 2 2 H 2 O All the isotopes react in the same way #1.

60. Hydrogen Atomic Number (protons) Atomic Mass

61. A Word of Caution…

62. The mass number (A) is NOT found on the periodic table The periodic table shows us atomic mass!

63. Atomic Mass = Average of all of the Mass Numbers in found in nature

64. H 1 H hydrogen-1 1

65. Isotopes of hydrogen 1 H or H “hydrogen” 2 H or H or D deuterium 3 H or H or T tritium 1111 2121 3131

66. Isotopes 1 H or H “hydrogen” 2 H or H or D deuterium 3 H or H or T tritium 1111 2121 3131 How many neutrons does 3 H have?

67. hydrogendeuterium tritium p n p p n n Which isotope is deuterium?

68. hydrogendeuterium tritium p n p p n n Which isotope is deuterium? Hydrogen Deuterium Tritium

69. 2 H 2 + O 2 2 H 2 O Does the little 2 after hydrogen have anything to do with isotopes? Since we are on hydrogen….

70. H 2 = hydrogen molecule made up of 2 hydrogen atoms

71. H 2 = hydrogen molecule made up of 2 hydrogen atoms Is H 2 an atom or a compound?

72. 2 H 2 + O 2 2 H 2 O Does the BIG 2 before hydrogen have anything to do with isotopes?

73. 2 H 2 means 2 hydrogen (H 2 ) molecules

74. Isotopes of hydrogen 1 H or H “hydrogen” 2 H or H or D deuterium 3 H or H or T tritium 1111 2121 3131

75. D 2 O vs H 2 O Does D 2 O freeze just like water?

76. Mass number (A) Atomic number (Z) 2 1 H Back to protons and neutrons …

77. ONE of the isotopes of _______. Element Symbol Element Name Atomic # # neutrons Mass number Cl18

78. ONE of the isotopes of chlorine. Element Symbol Element Name Atomic # # neutrons Mass number ClChlorine171835

79. Try this on your own Element Symbol Element Name Atomic # # neutrons Mass number Iron56

80. Element Symbol Element Name Atomic # # neutrons Mass number FeIron263056 Remember! Mass # = Atomic # + # neutrons

81. Rn Rn Rn Rn 224 86 223 86 222 86 221 86 220 86 219 86 218 86 217 86 216 86 215 86 214 86 213 86 212 86 211 86 210 86 209 86 208 86 207 86 206 86 205 86 And back to isotopes …

82. Isotopes 1) EVERY element on the periodic table has different isotopes.

83. Isotopes of hydrogen 1 H or H “hydrogen” 2 H or H or D deuterium 3 H or H or T tritium 1111 2121 3131

84. Carbon 12 C or C 13 C or C 14 C or C 12 6 13 6 14 6

85. Carbon 12 C or C 13 C or C 14 C or C 12 6 13 6 14 6 What can people find out from isotopes? 98.89% 1.11% Trace

86. When / How did life start on Earth? 12 C or C 13 C or C 14 C or C 98.89% 1.11% Trace 12 6 13 6 14 6

87. When / How did life start on Earth? 12 C or C 13 C or C 14 C or C 98.89% 1.11% Trace 12 6 13 6 14 6 We’re talking over 4 billion years ago!

88. Remember… All the isotopes react in the same way.

89. Carbon-12 vs Carbon-13 Most living things depend on carbon for their livelihood… Photosynthesis and respiration, for example

90. Carbon-12 vs Carbon-13 But do they use all carbon isotopes equally? Most living things depend on carbon for their livelihood…

91. Carbon-12 vs Carbon-13 Living organisms can use 12 C easier than 13 C. Remains of early organisms (fossil fuels, coal) tend to be rich in 12 C while rocks are rich in 13 C. But do they use each isotope equally?

92. Isotopes Some elements have stable isotopes. Some elements have only radioactive isotopes. Can you tell from the periodic table?

93. Rn Rn Rn Rn 224 86 223 86 222 86 221 86 220 86 219 86 218 86 217 86 216 86 215 86 214 86 213 86 212 86 211 86 210 86 209 86 208 86 207 86 206 86 205 86 All radioactive! No stable isotopes

94. Watch out for the word “stable”. Stable vs. radioactive Stable vs. chemically reactive

95. Isotopes 3) Isotopes are naturally abundant in different concentrations

96. 1 H “hydrogen” 99.985% 2 H deuterium 0.015% 3 H tritium trace amount

97. H 2 H 2 + O 2 Was there any D 2 or T 2 in these balloons?

98. Isotopes 4) Behave almost IDENTICALLY in chemical reactions

99. Chemical Reactions 2 H 2 + O 2  2 H 2 O 2 D 2 + O 2  2 D 2 O 2 T 2 + O 2  2 T 2 O