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Title: Unit 14: The Periodic Table and Nuclear Chemistry


1
Unit 14 The Periodic Table andNuclear Chemistry
  • Tyna L. Meeks

2
The Periodic Table
  • Every substance has characteristic properties
    that distinguish it from other substances, thus
    allowing it to be identified
  • PHYSICAL PROPERTIES
  • Physical changes are changes that occur without
    altering the identity of the substance in any
    way.

3
The Periodic Table
  • Every substance has the potential to be combined
    with another substance to form a brand new
    substance
  • CHEMICAL PROPERTIES
  • Chemical changes will always create a new
    substance. Chemical changes can often be
    detected by the formation of a gas, solid, color
    change, a change on the surface, or temperature
    change

4
The Periodic Table
  • Vocab Review
  • Atom Element
  • Electron Compound
  • Ion Molecule
  • Neutron Nucleus
  • Proton

5
Topic 1 The Atom
  • The Pattern of Atomic Numbers
  • Shortcut 12C 14C
  • 6 6

6
Topic 1 The Atom
  • What else is in the box? 12.0 C 4
  • 6
  • 2-4

7
The Periodic Table
  • When considering an atom, keep this in mind
  • number of protons must equal number of electrons
    (atoms are neutral after all)
  • number of neutrons can vary
  • if you have two atoms of the same element, they
    must have the same atomic number but different
    mass numbers ISOTOPES

8
The Periodic Table
  • The number of protons, called the ATOMIC NUMBER,
    distinguishes atoms of different elements.
  • The atomic number identifies every atom as a
    particular element.
  • BUT, the atomic number is not the atomic weight.

9
The Periodic Table
  • There is another particle in the atom that is
    neutral, but has mass. This particle is called a
    NEUTRON!
  • Located in the nucleus
  • All mass of atom is in nucleus
  • Nucleus is made up of protons and neutrons
    ONLY!!!
  • Atomic weight is equal to the average of all
    known isotopes

10
The Periodic Table
  • Valence electrons
  • Electrons in the highest principal energy levels
    are the electrons that can be used for bonding
  • arranged around the symbol of the element to
    easily identify bonding electrons
  • this symbol arrangement is called the Lewis Dot
    Structure

11
The Periodic Table
  • One element differs from another because its
    atoms have properties that differ from those of
    all other elements.
  • Elements can be grouped, or classified, in
    several ways according to similarities and
    differences in their properties.

12
The Periodic Table
  • In an effort to impose some organization on the
    information related to the elements, several
    scientists tried to place elements with similar
    properties near one another in a chart.
  • - atomic weight
  • - combining capacity

13
The Periodic Table
14
The Periodic Table
Original Periodic Law - atomic mass -
reactivity with oxygen Modern Periodic Law -
atomic number
15
The Periodic Table
  • Similar chemicals were placed in vertical columns
    (GROUPS)
  • Horizontal arrangements were done based on atomic
    weight (PERIODS)

16
The Periodic Table
17
The Periodic Table
Know the names of these following
groups Alkali Metals Alkaline Earth
Metals Transition Metals Chalcogens Halogens N
oble Gases
18
The Periodic Table
  • Simplest classification?
  • Metal, Nonmetal, or Metalloid

19
The Periodic Table
  • Simplest classification?
  • Metal Nonmetal Metalloid
  • malleable brittle both
  • ductile mostly gases
  • luster lack luster, dull
  • conductors non-conductors
  • mostly solids

20
The Periodic Table
  • Simplest classification?
  • Metal Nonmetal
  • higher densities lower densities
  • lose electrons gain electrons
  • to form () to form (-)
  • ions that are ions that are
  • smaller than larger than
  • atom atom

21
The Periodic Table
  • Special cases?
  • Transition Metals Noble Gases
  • d block Group 18
  • create colored completely
  • solutions unreactive

22
The Periodic Table
  • Homework pg 83-85, ques. 1-29

23
The Periodic Table
  • Homework pg 83-85, ques. 1-29
  • 1. 1 9. 3 17. 3 25. 3
  • 2. 2 10. 1 18. 3 26. 3
  • 3. 2 11. 1 19. 1 27. 2
  • 4. 4 12. 4 20. 4 28. 4
  • 5. 2 13. 3 21. 3 29. 2
  • 6. 2 14. 3 22. 1
  • 7. 4 15. 1 23. 3
  • 8. 2 16. 4 24. 3

24
The Periodic Table
  • Atomic Size Atomic Radius
  • Size of an atom is due to two things
  • Number of electron shells
  • Number of protons the atom has if its in the
    same shell

25
The Periodic Table
  • Atomic Size Atomic Radius
  • 1. As you go up or down the group, the size
    changes based on the number of electron shells
  • - down the group, size gets bigger, because
    youve added electron shells
  • - up the group, size gets smaller, because
    youre losing electron shells

26
The Periodic Table
  • Atomic Size Atomic Radius
  • 2. As you go across the SAME period, the size
    changes based on the number of protons in the
    nucleus
  • - more protons smaller atom
  • moving to the right
  • - less protons bigger atom
  • moving to the left

27
The Periodic Table
  • Ionization Energies Energy needed to LOSE
    an electron
  • Ionization Energy is due to one thing
  • 1. the bigger an metallic atom is the easier it
    is to give away the farthest, outermost, electron

28
The Periodic Table
  • Lets think about it
  • the more energy needed to force an atom to lose
    an electron, the less the atom wants to lose the
    electron
  • who wants to lose electrons?
  • how much energy do they charge?

29
The Periodic Table
  • Think, the fewer valence electrons a metal has,
    the easier it is to give them away
  • Group 1 has the fewest electrons, and therefore
    charges the least ionization energy
  • Group 18 has a full shell and cannot afford to
    lose any electrons so they charge the highest
    ionization energy
  • Goes from METALLIC to NONMETALLIC

30
The Periodic Table
  • 1. the bigger a metallic atom is, the easier it
    is to give away the farthest, outermost, electron
  • The largest atom in a group is at the bottom
  • Larger atoms charge less energy to remove the
    outermost electron
  • Ionization energies decrease as you go down the
    group

31
The Periodic Table
  • As you go down a group
  • Atom size INCREASES
  • Ionization energy DECREASES

32
The Periodic Table
  • As you go across a period
  • Atom size DECREASES
  • Ionization energy INCREASES

33
The Periodic Table
  • Electronegativities ability to attract an
    electron
  • Electronegativity is due to one thing
  • 1. the bigger an atom is the harder it is to
    attract an electron towards the nucleus

34
The Periodic Table
  • Lets think about it
  • who wants to gain electrons?
  • How badly do they want the electrons?
  • If both atoms want to gain an electron, the atom
    who wants it more holds it closer to its nuclear
    charge, creating a polar bond

35
The Periodic Table
  • Think, the smaller the atom is, the higher its
    nuclear charge is
  • Group 18 has a full shell, and is not interested
    in attracting any electrons, even though it is
    the smallest
  • Group 17 has an almost full shell and is the next
    smallest in size, therefore creating the highest
    attractive force
  • Group 1 has a nearly empty shell, not interested
    in attracting any electrons, and is the largest
    in the period
  • Goes from NONMETALLIC to METALLIC

36
The Periodic Table
  • 1. the smaller an atom is, the easier it is to
    attract an electron
  • The smallest atom in a group is at the top
  • Smaller atoms attract electrons easier than
    larger atoms
  • Electronegativities decrease as you go down the
    group

37
The Periodic Table
  • As you go down a group
  • Atom size INCREASES
  • Electronegativity DECREASES

38
The Periodic Table
  • As you go across a period
  • Atom size DECREASES
  • Electronegativity INCREASES

39
The Periodic Table
  • Allotropes
  • two or more forms of the same element that have
    distinctly different physical and chemical
    properties
  • O2 and O3 oxygen and ozone respectively
  • white phosphorous vs. red phosphorous

40
The Periodic Table
  • Allotropes
  • carbon also exists in three allotropic forms

41
The Periodic Table
  • Homework pg 73-75, ques. 30-90 even

42
The Periodic Table
  • Homework pg 73-75, ques. 30-90 even
  • 30. 4 38. 2 46. 2 54. 3
  • 31. 39. 47. 55.
  • 32. 3 40. 4 48. 4 56. 2
  • 33. 41. 49. 57.
  • 34. 1 42. 1 50. 1 58. 3
  • 35. 43. 51. 59.
  • 36. 4 44. 2 52. 4 60. 1
  • 37. 45. 53. 61.

43
The Periodic Table
  • Homework pg 73-75, ques. 30-90 even
  • 62. 3 70. 1
  • 63. 71.
  • 64. 1 72. 3
  • 65. 73.
  • 66. 1 74. 2
  • 67. 75.
  • 68. 2 76. Na has more protons, which
  • 69. makes it smaller

44
The Periodic Table
  • Homework pg 73-75, ques. 30-90 even
  • 78. Atomic number defines the element, not mass,
    using mass causes error
  • 80. MBr3 M2O3 valence e-
  • 82. smallest C largest Al
  • highest IE C lowest IE Al

45
The Periodic Table
  • Homework pg 73-75, ques. 30-90 even
  • 84. Metals on left move towards nonmetals on the
    right, going through metalloids which have both
    characteristics, to the noble gases which have
    full shells
  • 86. It only has 1 electron to lose before it
    gets a stable octet
  • 88. MgX2
  • 90. I and Te Ni and Co

46
Nuclear Chemistry
  • The Great Discovery
  • Models of the atoms took off during the
    investigations involving radiation
  • fluorescence
  • cathode rays
  • x-rays

47
Nuclear Chemistry
  • The Great Discovery
  • Cathode Rays

48
Nuclear Chemistry
  • The Great Discovery
  • X-rays

49
Nuclear Chemistry
  • The Great Discovery
  • Becquerels mistake

50
Nuclear Chemistry
  • Nuclear Radiation
  • Gamma pure energy, highest form of energy on
    electromagnetic spectrum

51
Nuclear Chemistry
  • Nuclear Radiation
  • All radiation can be classified two ways,
    ionizing and nonionizing
  • Nonionizing radiation is very low in energy-
    transfers its energy to matter causing the atoms
    to vibrate or move the electrons to higher energy
    states

52
Nuclear Chemistry
  • Nuclear Radiation
  • All radiation can be classified two ways,
    ionizing and nonionizing
  • Ionizing radiation is very high in energy-
    includes all nuclear reactions, the amount of
    energy found here is enough to eject an electron
    completely from its atom

53
Nuclear Chemistry
  • Nuclear Radiation
  • Nuclear Radiation is a form of ionizing radiation
    that results in changes in the nuclei of atoms
  • Most atoms are stable and their nuclei do not
    change (transmutate)
  • - Unstable nuclei are created by unbalanced
    proportions of neutrons to protons in nucleus

54
Nuclear Chemistry
  • Nuclear Radiation
  • These unstable nuclei undergo changes to become
    stable, and eject particles from the nucleus to
    get to a stable proportion
  • Three types of radiation are normal
  • ALPHA
  • BETA
  • GAMMA

55
Nuclear Chemistry
  • Nuclear Radiation ( Table O)
  • Alpha a helium nucleus composed of two protons
    and two neutrons 4He2
  • Beta a high speed electron 0e-1
  • Positron a high speed positively charge
    electron 0e1
  • Neutron alters mass, not charge 1n0
  • Gamma pure energy 0g0

56
Nuclear Chemistry
  • Nuclear Radiation
  • Forms of energy can be separated using magnetic
    and electric fields

57
Nuclear Chemistry
  • Architecture of Atoms
  • Review
  • nucleus has two particles (nucleons)
  • neutron, neutral charge
  • proton, positive charge
  • electrons have 1/1826 the mass of a proton
  • negative charge

58
Nuclear Chemistry
  • Architecture of Atoms
  • Review
  • atomic notation 14
    C 6

59
Nuclear Chemistry
  • Isotopes in Nature
  • All atoms have the ability to have varying
    amounts of neutrons
  • ISOTOPES
  • The atomic mass listed on periodic table is an
    average weight of all isotopes of the element
    found in nature

60
Nuclear Chemistry
  • Isotopes in Nature
  • To calculate atomic weights, multiply each weight
    of the atom by the percent it is found in nature.
    Add all your fractions together, and divide by
    100...

61
Nuclear Chemistry
  • Isotopes in Nature
  • If Carbon is found in nature 98.89 as C-12, and
    1.108 as C-13, what is the average weight?

62
Nuclear Chemistry
  • Isotopes in Nature
  • If Carbon is found in nature 98.89 as C-12, and
    1.108 as C-13, what is the average weight?
  • 98.89 12 amu 1186.68

63
Nuclear Chemistry
  • Isotopes in Nature
  • If Carbon is found in nature 98.89 as C-12, and
    1.108 as C-13, what is the average weight?
  • 98.89 12 amu 1186.68
  • 1.108 13 amu 14.404

64
Nuclear Chemistry
  • Isotopes in Nature
  • If Carbon is found in nature 98.89 as C-12, and
    1.108 as C-13, what is the average weight?
  • 98.89 12 amu 1186.68
  • 1.108 13 amu 14.404
  • 100 1201.084

65
Nuclear Chemistry
  • Isotopes in Nature
  • If Carbon is found in nature 98.89 as C-12, and
    1.108 as C-13, what is the average weight?
  • 98.89 12 amu 1186.68
  • 1.108 13 amu 14.404
  • 100 1201.084
  • Avg 12.011 amu

66
Nuclear Chemistry
  • Radioisotopes
  • For any element, an isotope that is unstable DUE
    TO PROPORTIONS OF PROTONS AND NEUTRONS and is
    radioactive is called a radioisotope

67
Nuclear Chemistry
  • Belt of Stability

68
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • If the atom isnt on the chart, stops at atomic
    number 82, then the proportions are so off huge
    particles need to be emitted
  • the most mass is ejected when a helium nucleus is
    split off, two protons and two neutrons leave
  • decrease atomic number by 2, mass number by 4
  • ALPHA emission

69
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • If the atom is too high, above the belt, then too
    many neutrons exist in the atom
  • the atom needs to lose neutrons
  • the neutron splits itself into a proton and an
    electron, keeps the proton and shoots out the
    electron
  • atomic number goes up by 1, mass number stays the
    same
  • BETA emission

70
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • If the atom is too low, below the belt, then too
    many protons exist in the atom
  • the atom needs to lose protons
  • the proton splits itself into a neutron and a
    positive electron, keeps the neutron and shoots
    out the positron
  • atomic number goes down by 1, mass number stays
    the same
  • POSITRON emission

71
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • Nuclear Equations can help keep track of the
    protons and neutrons for you.
  • 1n0 ? 1p1 0e-1 make sure all
    numbers add up left right 1p1 ? 1n0
    0e1

72
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • Nuclear Equations can also help you identify the
    new element created.
  • 226Ra88 ? X 4He2
  • solve numbers left right, look up the atomic
    number you solve for and that is your new element

73
Nuclear Chemistry
  • Transmutation change across the nucleus
  • Natural ONE reactant, decays to 2 or more
    products
  • Artificial TWO reactants, decays to 2 or more
    products

74
Nuclear Chemistry
  • Extending the Periodic Table
  • 23 transuranium elements (atomic numbers greater
    than 92) have been added
  • when a scientist creates a new element that
    stabilizes long enough to take measurements of,
    they get to name it...

75
Nuclear Chemistry
  • Transmutations
  • Unstable nuclei that decay spontaneously are
    natural transmutations
  • Bombarding a nucleus to force it to become
    unstable creates an artificial transmutation

76
Nuclear Chemistry
  • Homework pg 178 and 179, 1-23

77
Nuclear Chemistry
  • Homework pg 178 and 179, 1-23
  • 1. 1 8. 1
  • 2. 2 9. 3
  • 3. 1 10. 1
  • 4. 4 11. 3
  • 5. 1 12. 3
  • 6. 4 13. 2
  • 7. 1 14. 3

78
Nuclear Chemistry
  • Homework pg 178 and 179, 1-23
  • 15.a) 210Pb82 ? 0e-1 210Bi83
  • b) 137Cs55 ? 0e-1 137Ba56
  • c) 222Rn86 ? 4He2 218Po84
  • d) 185Au79 ? 4He2 181Ir77
  • e) 53Fe26 ? 0e1 53Mn25
  • f) 37Ca20 ? 0e1 37K19

79
Nuclear Chemistry
  • Homework pg 178 and 179, 1-23
  • 16. 4 21. 2
  • 17. 1 22. 1
  • 18. 2 23. 1
  • 19. 2
  • 20. 1

80
Nuclear Chemistry
  • Unleashing Nuclear Forces
  • The most famous artificial transmutation is
    nuclear fission.

81
Nuclear Chemistry
  • Unleashing Nuclear Forces
  • During FISSION, as the atom splits apart, mass is
    lost
  • This seems to defy the Conservation of Mass,
    however, Einstein realized that the mass is
    actually converted into energy
  • E mc2

82
Nuclear Chemistry
  • Unleashing Nuclear Forces
  • During FISSION, as the atom splits apart, mass is
    lost
  • It takes in incredible amount of force to hold a
    nucleus together remember all protons are
    positively charged and are repelling each other
  • Overcoming these forces and splitting one large
    nuclei into 2 smaller nuclei causes the
    conversion of mass into energy

83
Nuclear Chemistry
  • Unleashing Nuclear Forces
  • 3 neutrons produced by every fission of
    uranium-235.
  • Number of fissions and energy released quickly
    escalates exponentially is unchecked
  • In order for a fission chain reaction to occur a
    minimum mass of material must be present
    (critical mass) - with minimum present only one
    neutron is effective in producing another fission

84
Nuclear Chemistry
85
Nuclear Chemistry
  • Nuclear Reactors
  • Uranium is enriched to about 3 U-235 and then
    used to form UO2 pellets that are encased in
    zirconium or stainless steel tubes
  • Rods composed of materials such as cadmium or
    boron control the fission process by absorbing
    neutrons
  • Called Control Rods
  • Moderators slow down neutrons so they can be
    captured more readily by the fuel

86
Nuclear Chemistry
  • Nuclear Reactors
  • A cooling liquid is circulated through the core
    to carry off heat generated by the nuclear
    fission.
  • Cooling liquid and moderator could be one and the
    same substance
  • Steam is used to drive a turbine connected to an
    electrical generator, however steam must be
    condensed so additional cooling liquid is
    required, generally acquired from lake or river

87
Nuclear Chemistry
  • Nuclear Reactors
  • Reactor is surrounded by a concrete shell to
    shield personnel and nearby residents from
    radiation
  • Reactor must be stopped periodically so that the
    fuel can be replaced or reprocessed
  • Spent fuel rods are being kept in storage at
    reactor sites
  • 20 half-lives are required for their
    radioactivity to reach levels acceptable for
    biological exposure (600 years)

88
Nuclear Chemistry
  • Nuclear Reactors

89
Nuclear Chemistry
  • Nuclear Reactors

90
Nuclear Chemistry
  • Nuclear Reactors

91
Nuclear Chemistry
  • Nuclear Reactors

92
Nuclear Chemistry
  • Nuclear Reactors

93
Nuclear Chemistry
  • Nuclear Fusion
  • This reaction requires the combining of two
    smaller nuclei to form heavier ones.
  • - occurs in our sun
  • - 2 hydrogen are fused to form a helium
  • 1H1 1H1 --gt 4He2

94
Nuclear Chemistry
  • Nuclear Fusion
  • appealing as an energy source because of
    availability of light isotopes and because fusion
    products are generally not radioactive
  • not presently used to generate energy because
    high energies are needed to overcome the
    repulsion between nuclei
  • reaction requires temps of about 40,000,000 K
  • these temps have only been achieved using a
    hydrogen bomb

95
Nuclear Chemistry
  • Nuclear Fusion

96
Nuclear Chemistry
  • Homework pg 180-181, 24-33

97
Nuclear Chemistry
  • Homework pg 180-181, 24-33
  • 24. 3 30. 2
  • 25. 2 31. 2
  • 26. 4 32. 1
  • 27. 2 33. 1
  • 28. 3
  • 29. 1

98
Nuclear Chemistry
  • Half Lives
  • When radioactive substances decay, they do so at
    a CONSTANT RATE
  • Each isotope has its own half-life
  • Reference Table N

100 50 25 12.5
99
Nuclear Chemistry
  • Half Lives
  • Most chromium atoms are stable, but Cr-51 is an
    unstable isotope with a half-life of 28 days.
  • What fraction of a sample of Cr-51 will remain
    after 168 days?

100
Nuclear Chemistry
  • Half Lives
  • Most chromium atoms are stable, but Cr-51 is an
    unstable isotope with a half-life of 28 days.
  • If a sample of Cr-51 has an original mass of 52.0
    g, what mass will remain after 168 days?

101
Nuclear Chemistry
  • Radioisotopes
  • in Medicine
  • Half Lives
  • can be determined
  • using a graphical
  • analysis of decay

102
Nuclear Chemistry
  • Homework pg 183, 34-47

103
Nuclear Chemistry
  • Homework pg 183, 34-47
  • 34. 3 42. 2
  • 35. 1 43. 4
  • 36. 2 44. 1
  • 37. 3 45. 3
  • 38. 4 46. 3
  • 39. 2 47. 4
  • 40. 4
  • 41. 3

104
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • Atoms are emitting this radiation to surroundings
    at all times - so your are absorbing radiation
    from your surroundings at all times!!

105
Nuclear Chemistry
  • Exposure to Ionizing Radiation
  • Some radiation is always naturally
    found in the body

106
Nuclear Chemistry
  • How much is safe?

107
Nuclear Chemistry
  • Natural radioactive Decay
  • Review
  • Alpha emission
  • Beta emission
  • Positron emission
  • Nuclear Equations

108
Nuclear Chemistry
  • Radon
  • Whats all the fuss about?

109
Nuclear Chemistry
  • Radiation Detectors
  • Geiger counter
  • Scintillation counters
  • Solid state detectors

110
Nuclear Chemistry
  • Radioisotopes in Medicine
  • Radioisotopes can be used for several purposes
  • Dating
  • Chemical Tracers
  • Industrial Applications
  • Medical Applications

111
Nuclear Chemistry
  • Radioisotopes in Medicine
  • The length of the half life of a substance can
    help predict certain things
  • Geologic dating is done using Uranium
  • Biological dating is done using Carbon

112
Nuclear Chemistry
  • Due to the constancy of half lives, C14 can be
    used as a molecular clock to determine the ages
    of different objects

Chap. 21.4
113
Nuclear Chemistry
  • Shroud of
  • Turin - face

114
Nuclear Chemistry
  • Shroud of Turin - hands

115
Nuclear Chemistry
  • Radioisotopes in Medicine
  • When radioactive substances decay, they do so at
    a CONSTANT RATE
  • Not dependent on temperature or pressure
  • This is a random event, you cannot predict when a
    molecule will begin to decay
  • However, you can predict the amount of substance
    that will decay in a given amount of time

116
Nuclear Chemistry
  • Radioisotopes in Medicine
  • Due to the detectors available, radioisotopes can
    be observed as they go through their chemical
    pathways.
  • P-31 is present in fertilizer and can be
    watched as it is taken into the plant

117
Nuclear Chemistry
  • Radioisotopes in Medicine
  • Due to the detectors available, radioisotopes can
    be observed as they go through their chemical
    pathways.
  • C-14 can be used to map metabolic processes as
    it moves through respiration cycles

118
Nuclear Chemistry
  • Radioisotopes in Medicine
  • All materials absorb radiation in unique ways, so
    strength of material and, and thickness of hidden
    materials can be determined by shooting radiation
    at them.

119
Nuclear Chemistry
  • Radioisotopes in Medicine

120
Nuclear Chemistry
  • Artificial Radioactivity
  • Atoms can be bombarded with particles as well, to
    force them to become unstable and decay
  • ARTIFICIAL TRANSMUTATION
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