2. 2 - 1 GS105 Chapter 3: Atoms & the Periodic Table AtomsElements Atomic Structure Spectroscope Identification The Periodic Table Periodic Trends

3. 2 - 2 GS105 stuff The stuff things are made of. Mass Volume Has Mass and Volume (takes up space). (Air, water, rocks, etc..) Matter What is Chemistry? “The study of Matter and its Changes.”

4. 2 - 3 GS105 Models of Matter All matter made of atoms. Atoms of same element are identical. Atoms are indivisible. Atoms of elements in set ratios form compounds. Explained Law of conservation of matter :

5. 2 - 4 GS105 Law of conservation of matter: Matter is neither lost nor gained during a chemical reaction. Models of Matter Law of Definite Proportions: In a compound, the constituent elements are always present in a definite proportion by mass. Ie. H 2 O is always 11.2% hydrogen and 88.8% oxygen by weight. Total mass of reactants = total mass of products Ie. C 12 H 22 O 11 is always 42.1% carbon 6.5% hydrogen and 51.4% oxygen by weight.

6. 2 - 5 GS105 Models of Matter All matter made of atoms. Atoms of same element are identical. Atoms are indivisible. Atoms of elements in set ratios form compounds. Explained Law of conservation of matter: Marie Curie 1898: Elements from radioactive decay shows that atoms can be divided.

7. 2 - 6 GS105 Models of Matter All matter made of atoms. Atoms of same element are identical. Atoms are indivisible. Atoms of elements in set ratios form compounds. Explained Law of conservation of matter: Marie Curie 1898: Elements from radioactive decay shows that atoms can be divided.

8. 2 - 7 GS105 Rutherford’s Gold-Foil Experiment  99% of + particles aimed at gold went straight through.  A few were deflected.  A few bounced back Conclusion:  Atoms are mostly empty space.  Atoms have a small, dense nucleus with + charge.

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10. 2 - 9 GS105 Models of Matter All matter made of atoms. Atoms of same element are identical. Atoms are indivisible. Atoms of elements in set ratios form compounds. Explained Law of conservation of matter: Marie Curie 1898: Elements from radioactive decay shows that atoms can be divided. Nucleus at center of atom. Nucleus is small, dense, and has + charge. Atoms are mostly empty space.

11. 2 - 10 GS105 A model of matter Atom Atom - The smallest unit of an element that is still that element. Molecule Molecule -The smallest unit of a pure substance that is still that substance. May contain > 1 atom or element May contain > 1 atom or element. ie. Aluminum (Al) ie. Water (H 2 O)

12. 2 - 11 GS105 Structure of the atom Nucleus + Small, dense, + charge in the center of an atom. containsprotons & neutrons + + + + ++

13. 2 - 12 GS105 Structure of the atom Nucleus (+) Electrons - - charged particles that surround the nucleus. Electrons nucleusorbitals Electrons moved around nucleus in orbitals.

14. 2 - 13 GS105 Structure of the atom nucleus The nucleus is a small part of an atom. If the nucleus was the size of a marble, the atom would fill a football stadium. The nucleus would weigh over 10,000 tons.

15. 2 - 14 GS105 Z Z = Atomic number # protons# electrons = # protons = # electrons X A Z A A = Atomic mass (amu) # protons + # neutrons = # protons + # neutrons + + + + ++ - - - - - - Atomic Symbols

16. 2 - 15 GS105 A A = Atomic mass # p + # n = # p + # n X A Z C # Z Z = Atomic # # p = # e C C = Charge = + or - values # # = Number of atoms in a formula. Atomic Symbols

17. 2 - 16 GS105 X 12 6 A A = Atomic mass # protons + # neutrons = # protons + # neutrons Z Z = Atomic number # protons# electrons = # protons = # electrons + + + + ++ - - - - - - 6 6 Atomic Symbols

18. 2 - 17 GS105 C 12 6 A A = Atomic mass # protons + # neutrons = # protons + # neutrons Z Z = Atomic number # protons# electrons = # protons = # electrons + + + + ++ - - - - - - Atomic Symbols

19. 2 - 18 GS105 Na 23 11 1+ A A = Atomic mass = p + n = 23 Z Z = Atomic # = p = 11 C C = Charge = +1 # # = 1 atom in formula. Sodium 1112 Atomic Symbols

20. 2 - 19 GS105 Ag 107.87 Silver 47 Atomic number Name of the element Elemental Symbol Atomic mass (weight) Atomic weightaverage Atomic weight = The average, relative mass of an atom in an element. Why is the atomic weight on the tables not a whole #?

21. 2 - 20 GS105 Isotopes of Hydrogen Isotopes = Isotopes = Atoms of the same element but having different masses. 1111 2121 3131 + H H H - + - + - Protium99.99% Deuterium0.01% Tritium Trace %

22. 2 - 21 GS105 Isotopes of Hydrogen Isotopes = Isotopes = Atoms of the same element but having different masses. 1111 2121 3131 + H H H - + - + - Average Atomic weight Average Atomic weight of Hydrogen 1.00794 amu = 1.00794 amu

23. 2 - 22 GS105 + + + + ++ Isotopes of Carbon - Average Atomic weight12.011 amu Average Atomic weight of C= 12.011 amu 98.89% C 6 12 C 6 13 C 6 14 + + + + ++ - 1.11% + + + + ++ - Trace % - - - - - - - - - - - - - - -

24. 2 - 23 GS105 Radioactive Isotopes C 614 + + + + ++ - - - - -- 3131 H +- Nucleus is unstable So falls apart (decays) Giving radioactive particles H-3C-14

25. 2 - 24 GS105 Average Atomic Mass Cl 1737 Cl 1735 35 (75.8) 100 75.8%24.2% + 37 (24.2) 100 = 35.45 amu

26. 2 - 25 GS105 ProtonsNeutronsElectrons The atomic symbol & isotopes P 3115 Ba 138 56 56 U 238 92 92 151516 5656 9292 82 146 Complete the table: 123

27. 2 - 26 GS105 SymbolAtomic # MassProtonsNeutrons Electrons Atomic Structure Be 1414 14 2814Si 1720171737Cl 44945 Complete the table: 123456

28. 2 - 27 GS105 Modern periodic table H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTa He RnAtPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC I A II A III A IV A V A VI A VIIA VIIIA III B IVB V B VIB VIIB VIII B IB IIB 12345671234567 Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es The periodic table helps us understand behavior,behavior, reactionsreactions propertiesproperties of the elements. Mendeleev, 1871 “Properties of the elements vary in a periodic manner.”

29. 2 - 28 GS105

30. 2 - 29 GS105

31. 2 - 30 GS105 A row or period He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B 12345671234567 Periods are assigned numbers Periods are assigned numbers

32. 2 - 31 GS105 Common group names H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTa He RnAtPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC I A III B IVB V B VIB VIIB VIII B IB IIB Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es Alkali Metals Alkaline Earth Metals HalogensHalogens Noble gases III A IV A V A VI A VIIA VIIIA II A Transition Metals LanthanidesLanthanides ActinidesActinides ChalcogensChalcogens

33. 2 - 32 GS105 Why do we have those rows on the bottom? H Li Na Cs Rb K LaBa Fr Be Mg Sr Ca Y AcRa Sc TlHgAuHfPtIrOsReWTa He RnAtPoBiPb CdAgZrPdRhRuTcMoNb ZnCuTiNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es This arrangement takes too much space and is hard to read.

34. 2 - 33 GS105 Names & Symbols He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B 12345671234567 Know the names & symbols Know the names & symbols

35. 2 - 34 GS105 At Te As Si B He Rn Xe I KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNi Co FeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es MetalsMetals Lustrous, malleable and ductile. Conductors (heat & electricity) Solids at room temp (except Hg) Lose electrons to non-metals. Lustrous, malleable and ductile. Conductors (heat & electricity) Solids at room temp (except Hg) Lose electrons to non-metals.

36. 2 - 35 GS105 He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B Non-metalsNon-metals Gasliquidsolid (dull, brittle) Gas, liquid, solid (dull, brittle) Poor conductors = Insulators Many are diatomic molecules. Gain e’s from metals Share e’s with other non-metals Gasliquidsolid (dull, brittle) Gas, liquid, solid (dull, brittle) Poor conductors = Insulators Many are diatomic molecules. Gain e’s from metals Share e’s with other non-metals

37. 2 - 36 GS105 He Rn Xe I KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLsBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B 3 - 11 MetaloidsMetaloids Intermediate properties Semi conductors Intermediate properties Semi conductors

38. 2 - 37 GS105 H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNi Co FeMnCrV InSn Ga Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es He Rn XeI KrBrSe ArClS NeFO P NC Sb Ge At Te As Si B MetaloidsMetaloids MetalsMetals Non-metalsNon-metals

39. 2 - 38 GS105 Elemental states at room temperature He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLaBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb AcRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es At Te As Si B Solid Liquid Gas 3 - 13 ©Chemeketa Community College: Chemistry for Allied Health

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41. 2 - 40 GS105 Models of Matter All matter made of atoms. Atoms of same element are identical. Atoms are indivisible. Atoms of elements in set ratios form compounds. Explained Law of conservation of matter: Marie Curie 1898: Elements from radioactive decay shows that atoms can be divided. Nucleus at center of atom. Nucleus is small, dense, and has + charge. Atoms are mostly empty space. Electrons in orbit around the nucleus. Energy causes electrons to “jump” to other orbits. (Ground state  excited state). Energy levels correspond to fixed wavelengths.

42. 2 - 41 GS105 Electronic arrangement A new layer is added for each row or period in the table.

43. 2 - 42 GS105 Electron arrangement 2 8 18 32 Electrons fill layers around nucleus Low  High Shells = Energy levels 2412 Mg

44. 2 - 43 GS10511H 73Li 42He IA IIA 94Be 2, 1 2, 2

45. 2 - 44 GS105115B 11H 73Li IA IIA IIIA 94Be 2, 1 2, 2 2, 3

46. 2 - 45 GS105115B 126C 137N IIIA IVA VA 2, 3 2, 4 2, 5

47. 2 - 46 GS10594Be 11H 73Li 42He 2010Ne 2311 Na 2412 Mg 4018 Ar IA IIA VIIIA 2, 1 2, 2 2, 8, 1 2, 8, 2 2, 8 2, 8, 8

48. 2 - 47 GS105 33 2412 Mg 11H 73Li 2311 Na 94Be 115B 2713 Al Valence electrons Where most chemical Reactions occur.1122 2, 1 2, 2 2, 8, 1 2, 8, 2 2, 3 2, 8, 3

49. 2 - 48 GS10511H 73Li 42He 94Be 2010Ne 2311 Na 2412 Mg 4018 Ar 881122 2, 1 2, 2 2, 8 2, 8, 1 2, 8, 2 2, 8, 8 Octet Rule

50. 2 - 49 GS105 The octet rule Atoms are most stable if they have a filled or empty outer layer of electrons. Except for H and He, a filled layer contains 8 electrons - an octet. Atoms gain, lose or share electrons to make a filled or empty outer layer. Atoms gain, lose or share electrons based on what is easiest.

51. 2 - 50 GS105 Periodic trends Certain properties of the elements exhibit a gradual change as we go either across a period or down a group. Knowing these trends can help in our understanding of chemical properties - We’ll look briefly at these trends for the representative elements. Valence Electrons Atomic size Electron affinity Electronegativity

52. 2 - 51 GS105 Group Numbers & Valence Electrons 4 - 6 1 223344556677 Representative Elements 88 Periodic trends

53. 2 - 52 GS10511H 73Li 2311 Na Electron-Dot (Lewis) Symbols Show only Valence Electrons H Li Na K Periodic trends

54. 2 - 53 GS105 H Li Na K He Be B C O F Ne N Mg Ca Al Ga Si Ge P As S Se ClBrArKr 1 234567 8 Electron-Dot Symbols Periodic trends

55. 2 - 54 GS105 Models of Matter All matter made of atoms. Atoms of same element are identical. Atoms are indivisible. Atoms of elements in set ratios form compounds. Explained Law of conservation of matter: Marie Curie 1898: Elements from radioactive decay shows that atoms can be divided. Nucleus at center of atom. Nucleus is small, dense, and has + charge. Atoms are mostly empty space. Electrons in orbit around the nucleus. Energy causes electrons to “jump” to other orbits. (Ground state  excited state). Energy levels correspond to fixed wavelengths. Orbitals within each energy level. Equation to determine probable location of electrons

56. 2 - 55 GS105 Orbitals

57. 2 - 56 GS105 Orbitals

58. 2 - 57 GS105 Orbitals

59. 2 - 58 GS105 Orbitals p (3) s (1) d (5) Each subshell contains orbitals which can hold a maximum of two electrons f (7)

60. 2 - 59 GS105 1s __ 2s __ 2p __ __ __ 3s __ 3p __ __ __ 4s __ 3d __ __ __ __ __ 5s __ 4p __ __ __ 4d __ __ __ __ __ 5p __ __ __ 6s __ 5d __ __ __ __ __ 4f __ __ __ __ __ __ __ 73Li 1s 2 2s 1 Electron Configuration

61. 2 - 60 GS105 1s __ 2s __ 2p __ __ __ 3s __ 3p __ __ __ 4s __ 3d __ __ __ __ __ 5s __ 4p __ __ __ 4d __ __ __ __ __ 5p __ __ __ 6s __ 5d __ __ __ __ __ 4f __ __ __ __ __ __ __ 1s 2 2s 2 2p 4 16 8 O Electron Configuration

62. 2 - 61 GS105 6s6p6d6f 5s5p5d5f 4s4p4d4f 3s3p3d 2s2p 1s Electron Configuration: Orbital Filling 6s6p6d6f 5s5p5d5f 4s4p4d4f 3s3p3d 2s2p 1s

63. 2 - 62 GS105 1s __ 2s __ 2p __ __ __ 3s __ 3p __ __ __ 4s __ 3d __ __ __ __ __ 5s __ 4p __ __ __ 4d __ __ __ __ __ 5p __ __ __ 6s __ 5d __ __ __ __ __ 4f __ __ __ __ __ __ __ 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 30 Zn [Ar] [Ar] 4s 2 3d 10 [Ar] [Ar] 3d 10 4s 2 Electron Configuration 6s6p6d6f 5s5p5d5f 4s4p4d4f 3s3p3d 2s2p 1s

64. 2 - 63 GS105 1s __ 2s __ 2p __ __ __ 3s __ 3p __ __ __ 4s __ 3d __ __ __ __ __ 5s __ 4p __ __ __ 4d __ __ __ __ __ 5p __ __ __ 6s __ 5d __ __ __ __ __ 4f __ __ __ __ __ __ __ 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 36 Kr [Ar]4p 6 [Ar] 4s 2 3d 10 4p 6 [Ar]4p 6 [Ar] 3d 10 4s 2 4p 6 Electron Configuration 6s6p6d6f 5s5p5d5f 4s4p4d4f 3s3p3d 2s2p 1s

65. 2 - 64 GS105 Atoms get smaller as you go across a period. Atomic Size Ba Sr Ca Mg Be Tl In Ga Al B Pb Sn Ge Si C Cs Rb K Na Li Bi Sb As P N Te Se S C I Br Cl F HAtomsgetlargerasyougodownagroup. Periodic trends

66. 2 - 65 GS105 Atoms get larger as you go down a group. A new shell is being added which is located further from the nucleus. Atoms get smaller as you go across a period. There are more protons being added to the nucleus as electrons are added to the outer shell. This higher positive charge attracts the electrons more strongly, making the atom smaller. (Air traffic control analogy) Atomic Size Periodic trends

67. 2 - 66 GS105 Lithium Atoms get smaller as you go across a period. Atomic Size

68. 2 - 67 GS105 Beryllium Atoms get smaller as you go across a period. Atomic Size

69. 2 - 68 GS105 Boron Atoms get smaller as you go across a period. Atomic Size

70. 2 - 69 GS105 Carbon Atoms get smaller as you go across a period. Atomic Size

71. 2 - 70 GS105 Nitrogen Atoms get smaller as you go across a period. Atomic Size

72. 2 - 71 GS105 Oxygen Atoms get smaller as you go across a period. Atomic Size

73. 2 - 72 GS105 Fluorine Atoms get smaller as you go across a period. Atomic Size

74. 2 - 73 GS105 Neon Atoms get smaller as you go across a period. Atomic Size

75. 2 - 74 GS105 Sodium Atomsgetlargerasyougodownagroup. Atomic Size

76. 2 - 75 GS105 Atoms get smaller as you go across a period. Atomic Size Ba Sr Ca Mg Be Tl In Ga Al B Pb Sn Ge Si C Cs Rb K Na Li Bi Sb As P N Te Se S C I Br Cl F HAtomsgetlargerasyougodownagroup. Periodic trends

77. 2 - 76 GS105 At I Br Cl Po Te Se S Bi Sb As P Pb Sn Ge Si FON Tl Na Cs Rb K Ba Mg Sr Ca In Ga Al H LiBeBC 4 - 50 ©Chemeketa Community College: Chemistry for Allied Health Periodic trends Relative ability of atoms to attract electrons. Electronegativity

78. 2 - 77 GS105 Electronegativity Relative ability of atoms to attract electrons. Periodic trends

79. 2 - 78 GS105 Summary of trends. As atomic size decreases  Attraction of nucleus for electrons increases.  Electrons are harder to remove.  Adding more electrons is easier.Summary Metals are larger so tend to lose electrons. Non-metals are smaller so tend to gain electrons. Periodic trends

80. 2 - 79 GS105 Inner vs. valence electrons Valence electrons Where most reactions occur. Inner electrons Not much happens here under normal conditions.

81. 2 - 80 GS105 The Continuous Spectrum white light When sunlight ( white light ) is passed thru a prism, a continuous rainbow of colors is observed. There appears to be light of every color in sunlight.

82. 2 - 81 GS105 Electromagetic Spectrum The Continuous Spectrum High EnergyLow Energy Long Wavelength Low Frequency Short Wavelength High Frequency

83. 2 - 82 GS105 Actually, most light waves cannot be seen by the human eye. The visible spectrum (violet to red) is a very small percentage of the entire electro- magnetic spectrum. Shorter wave length light is high energy. Gamma rays, X-rays, UV, etc.. (Gamma rays, X-rays, UV, etc..) Larger wave length light is low energy. IR, Microwaves, Radio, etc.. (IR, Microwaves, Radio, etc..) The Continuous Spectrum

84. 2 - 83 GS105 The Discrete Spectrum ! But when light from elements is passed thru a prism, a continuous spectrum is not observed. hydrogen, From the red glow of hydrogen, 4 lines emerged.

85. 2 - 84 GS105 The Discrete Spectrum ! H Hg Ne

86. 2 - 85 GS10573Li 1 __ 2 __ 3 __ 4 __ 5 __ 6 __ Excitation of electrons Add Energy to kick electrons to higher level 1 __ 2 __ 3 __ 4 __ 5 __ 6 __

87. 2 - 86 GS105 Excitation of electrons Some of these discrete Quantities (Quanta) of Energy appear as colors Excited electrons fall back giving back the energy it took to excite them

88. 2 - 87 GS105 1 _____ 2 _____ 3 _____ 4 _____ 5 _____ 6 _____ 11H Excitation of electrons Add Energy to kick e- to higher level 1 _____ 2 _____ 3 _____ 4 _____ 5 _____ 6 _____ E Energy is given back when e- falls back to lower level 656 nm 486 nm 434 nm 410 nm Some of these discrete Quantities (Quanta) of Energy appear as colors

89. 2 - 88 GS105 Emission Spectrum of Hydrogen https://www.khanacademy.org/science/chemistry/electronic-structure-of- atoms/bohr-model-hydrogen/v/emission-spectrum-of-hydrogen Explanation of 4 line spectrum of Hydrogen: (10:49min)

90. 2 - 89 GS105 Excitation of electrons

91. 2 - 90 GS105 Energy Excitation of electrons Principle quantum numbers designate shells

92. 2 - 91 GS105 Videos Video: IBM Atom Movie: http://www.dvice.com/2013-5-1/ibm-uses-individual-molecules-make- smallest-movie-ever Youtube: have you ever seen an atom? (2:31 min) https://www.youtube.com/watch?v=yqLlgIaz1L0 Video: The Elements Organized: the periodic table (24:59 min) https://mail.google.com/mail/u/0/?shva=1#inbox/14ad6986b5bd0 cbd?projector=1 Video: How does an LED work? (1:17 min) https://mail.google.com/mail/u/0/?shva=1#inbox/14ad6986b5bd0 cbd?projector=1 TED: Just how small are atoms? (5:27 min) Jon B. http://www.ted.com/talks/just_how_small_is_an_atom

93. 2 - 92 GS105 Periodic Table: Families Get into families: What is your family name? What do you have in common? What are your properties? Metal/ Nonmetal?; solid/liquid/gas?; appearance? How do you behave? Which whom do like to make compounds? Anything unique/memorable about any of your family members?

94. 2 - 93 GS105 Learning Check

95. 2 - 94 GS105 Learning Check: Solution