Unit 5 test

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jb124
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285712
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Unit 5 test
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2014-10-13 15:55:09
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elements
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science
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organizing the elements
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  1. one of the first scientists to design a way of organizing the elements
    Dmitri Mendeleev
  2. how did Dmitri Mendeleev list the elements?
    by increasing atomic mass
  3. when was the first periodic table of the elements published?
    1869 by Mendeleev
  4. what did question marks and/or gaps indicate in Mendeleev's periodic table?
    predicted new elements that would be discovered
  5. considered the father of the periodic table
    Mendeleev
  6. what element was named in Mendeleev's honor?
    mendelevium
  7. what was wrong with Mendeleev's periodic table?
    some elements did not quite fit the pattern - elements' similar properties did not appear at regular intervals
  8. who arranged the elements by atomic number rather than by atomic mass?
    Henry Moseley
  9. what is the atomic number?
    number of protons in an atom of the element
  10. disagreement or difference between apparent facts
    discrepancy
  11. law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements
    periodic law
  12. what does the periodic table in this book list?
    • atomic number
    • symbol
    • name
    • average atomic mass
  13. each row of the periodic table
    period
  14. how many periods does the periodic table have?
    7
  15. what happens as you move from left to right across a period?
    properties such as reactivity and conductivity change and elements become less metallic
  16. each column of the periodic table
    group
  17. what similarities do elements in each group have?
    similar chemical properties
  18. what are chemical properties related to in each element?
    number of electrons
  19. for a neutral atom, the number of protons equals?
    number of electrons
  20. the periodic trends in the periodic table are the result of what?
    electron arrangement
  21. by what are the chemical properties of each group largely determined?
    number of valence electrons
  22. where are the valence electrons located?
    closest to the outside of the atom and are sometimes considered part of an outer "shell" of electrons
  23. what determines many of the chemical properties of an element?
    the number of valence electrons
  24. an element's location in the periodic table is related to what?
    electron arrangement
  25. a charged atom
    ion
  26. process in which atoms may lose or gain valence electrons so that they have a filled outermost orbital
    ionization
  27. what happens if an atom gains or loses electrons?
    it no longer has an equal number of electrons and protons
  28. what happens when an atom no longer has an equal number of electrons and protons, and the charges do not cancel completely?
    the atom has a net electric charge
  29. what do group 1 elements form?
    positive ions
  30. positive ion
    cation
  31. what do group 17 elements form?
    negative ions
  32. negative ion
    anion
  33. how many categories are the 18 groups of the elements further classified?
    3
  34. what are the 3 categories?
    • metals
    • nonmetals
    • semiconductors
  35. in which category are most elements?
    metals
  36. properties of metals
    • shiny solids that can be stretched and shaped
    • good conductors of heat and electricity
  37. examples of metals
    • gold
    • platinum
    • copper
  38. which category is found on the right side of the periodic table?
    nonmetals, except hydrogen
  39. examples of nonmetals
    • carbon
    • oxygen
    • helium
  40. properties of nonmetals
    • may be solids, liquids or gases at room temperature
    • solids are often dull and brittle
    • poor conductors of heat and electricity
  41. materials that do not conduct heat or electricity well
    insulators
  42. category of 6 elements that can conduct electricity under certain conditions
    semiconductors
  43. metalloids
    semiconductors
  44. examples of semiconductors
    • silicon
    • germanium
  45. unit in which one or more groups in the periodic table categorized
    family
  46. how many families can elements be classified?
    5
  47. what categorizes a family?
    the elements in a family have the same number of valence electrons
  48. examples of families of metals
    • alkali metals
    • alkaline-earth metals
    • transition metals
  49. which family of metals is very reactive?
    alkali metals
  50. why is an atom of an alkali metal very reactive?
    it has one valence electron that can easily be removed to form a positive ion
  51. properties of alkaline-earth metals
    • harder
    • denser
    • stronger
    • have higher melting points than alkali metals
  52. how many valence electrons do atoms of alkaline-earth metals have?
    2
  53. example of alkaline-earth metal
    calcium
  54. alkaline-earth metals combine with other elements to form ___
    compounds
  55. lightest of all structural metals
    magnesium
  56. in which groups are transition metals found?
    groups 3-12
  57. example of transition metal
    gold
  58. if an atom of gold loses only one electron, what does it form?
    Au+
  59. if an atom of gold loses 3 electrons, what does it form?
    Au3+
  60. properties of transition metals
    • harder
    • more dense
    • higher melting points than alkali and alkaline-earth metals
  61. metals that can use the inner shell before using the outer shell to bond
    transition metal
  62. nuclei of an atom continually decay to produce different elements
    radioactive
  63. most stable isotope
    technetium-99
  64. what is technetium-99 used for?
    to diagnose cancer as well as other medical problems that occur in soft tissues of the body
  65. most useful isotope
    promethium-147
  66. where are tiny amounts of americium-241 found?
    most household smoke detectors
  67. families of nonmetals include?
    • noble gases
    • halogens
  68. one of the elements of group 18 of the periodic table
    noble gas
  69. example of noble gas
    • neon
    • helium
    • argon
  70. how do noble gases exist?
    as single atoms instead of as molecules
  71. unreactive
    inert
  72. because of the unreactivity of noble gases, what happens with electrons?
    • noble gases do not gain or lose electrons to form ions
    • most do not join with other atoms to form compounds
  73. how is helium used?
    used to give lifts to blimps and balloons
  74. how is argon used?
    to fill light bulbs because its lack of reactivity prevents the bulbs' filaments from burning
  75. most reactive nonmetals
    halogens
  76. how many valence electrons do halogens have?
    7
  77. how do halogens become stable?
    with the addition of a single electron
  78. compounds that result from combinations of halogen with other metals
    salts
  79. how is chlorine used?
    to kill bacteria in pools
  80. NaCl
    table salt
  81. a third form of carbon confirmed in 1990
    fullerenes
  82. most famous fullerene
    buckminsterfullerene
  83. what kind of atoms (usually in the form of compounds) account for 28% of the Earth's crust?
    silicon
  84. most abundant element in the universe
    hydrogen

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