Test 10_05_12 Rad Science Chapter 2_cb

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Test 10_05_12 Rad Science Chapter 2_cb
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Test 10_05_12 Rad Science Chapter 2_cb
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  1. The center of the atom
    Nucleus
  2. Ernest Rutherford introduced the nuclear model, which described the atom as containing a small, dense, (positive or negative) charged center surrounded by a (positive or negative) cloud of electrons.
    • Positive
    • Negative
  3. Bohr's model was a miniature solar system in which the electrons revolved about the nucleus in prescribed orbits or _____.
    energy levels
  4. Bohr Atom represents the best way to picture the atom, although the details of atomic structure are more accurately described by a newer model called
    quantum chromodynamics (QCD)
  5. "Atom smashers", the structure of the atomic nucleus is slowly being mapped and identified.
    particle accelerators
  6. The three primary constituents of an atom also known as fundamental particles:
    • electon
    • proton
    • neutron
  7. The 3 fundamental particles of an atom are:
    • electron
    • proton
    • neutron
  8. very small particles that carry one unit of negative electric charge.
    electons
  9. An atomic particle is extremely small, its mass is expressed in
    Atomic Mass Unit (amu)
  10. One atomic mass unit is equal to ___ the mass of a carbon-12 atom.
    • one twelfth
    • 1/12
  11. When precision is not necessary, a system of whole numbers used is called
    mass numbers
  12. The atomic mass number of an electron is
    zero
  13. The nucleus contains particles called
    nucleons
  14. The 2 types of nucleons
    • protons
    • neutrons
  15. Protons and neutrons both have nearly how times the mass of an electron?
    2000
  16. Essentially empty space.
    Atom
  17. The number of protons determines the
    chemical element
  18. Atoms that have the same number of protons but differ in the number of neutrons are
    isotopes
  19. Electrons can exist only in certain ___, which represent different electron binding energies or ____ ____.
    • shells
    • energy levels
  20. For identification purposes, electron orbital shells are given the codes (name 1st four) to represent the relative binding energies of electrons from closest to the nucleus to farthest from the nucleus
    K, L, M, N
  21. The closer an electron is to the nucleus, what energy is greater?
    binding energy
  22. What are electrically neutral in their normal state?
    Atom
  23. The removal or addition of an orbital electron from an atom
    Ionization
  24. The mass number of electrons that can exist in each shell (decrease or increase) with the distance of the shell from the nucleus.
    increases
  25. The total number of electrons in the orbital shells is exactly equal to the number of ____ in the _____
    • protons
    • nucleus
  26. An atom has an extra electron or has had an electron removed is
    ionized
  27. An ionized atom is not electrically neutral but carries a charge equal in magnitude to the difference between the numbers of ____ and ____
    • electons
    • protons
  28. How the maximum electrons per shell is calculated
    2n2
  29. What is the maximum number of electrons that can exist in the O shell (shell number 5)
    • n = 5
    • 2n2 = 2(5)2
    •        = 2 (25)
    •        = 50 electrons
  30. What is the shell number for each symbol:
    K, L, M, N, O, P, Q
    • K = shell 1
    • L = shell 2
    • M = shell 3
    • N = shell 4
    • O = shell 5
    • P = shell 6
    • Q = shell 7
  31. Calculate the number of electrons that can occupy each electron shell for the following: 2n2
    K, L, M, N
    • K = 2(12)
    •     = 2(1) = 2 electrons

    • L = 2(22)
    •    = 2(4) = 8 electrons

    • M = 2(32)
    •      =2(9) = 18 electrons

    • N = 2(42)
    •     = 2(16) = 32 electrons
  32. No outer shell can contain more than ____ electrons
    8
  33. What does Physicists call the shell number n
    principal quantum number
  34. "center-seeking" force, which results from a basic law of electricity that states that opposite charges attract one another and like charges repel.
    centripetal force
  35. The force that keeps an electron in orbit is
    centripetal force
  36. The strength of attachment of an electron to the nucleus is called
    electron binding energy
  37. Note:
    K-shell electrons have higher binding energies than L-shell electrons, L-shell electrons are more tightly bound to the nucleus than M-shell electrons, and so forth.
  38. The atomic mass number and the precise mass of an atom are (equal or not equal)
    equal
  39. A whole number that is equal to the number of nucleons in the atom
    atomic mass number
  40. The characteristic mass of an element is determined by the relative abundance of isotopes and their perspective atomic masses
    elemental mass
  41. Atoms that have the same atomic number but different atomic mass numbers are
    isotopes
  42. Atomic nuclei that have the same atomic mass number but different atomic numbers are
    isobars
  43. The atoms that have different numbers of protons and different numbers of neutrons but the same total number of nucleons
    Isobars
  44. Atoms that have the same number of neutrons but different numbers of protons are
    isotones
  45. Atoms with different atomic numbers and different mass numbers but a constant value for the quantity A-Z.
    Isotones
  46. Atoms with the same number of neutrons in the nucleus
    Isotones
  47. Have the same atomic number and the same atomic mass number.
    Isomer
  48. Atoms of various elements may combine to form structures called
    Molecules
  49. Any quantity of one type of molecule
    Chemical compound
  50. Similarly, hydrogen, oxygen, carbon, and nitrogen compose more than ____% of the human body.
    95%
  51. At approximately what % water molecules make up of the human body?
    80%
  52. Oxygen and hydrogen combine into water through what type of bonds.
    Covalent bonds
  53. Sodium and chlorine combine into salt through what type of bond?
    Ionic bonds
  54. A measurable quantity of sodium bicarbonate constitutes a chemical compound commonly called
    Baking soda
  55. Some atoms exist in an abnormally excited state characterized by an unstable nucleus. To reach stability, the nucleus spontaneously emits particles and energy and transform itself into another atom. This process is called _____ _____ or _____ _____
    • Radioactive disintegration
    • Radioactive decay
  56. Any nucleus that emits radiation; Only nuclei that undergo radioactive decay are
    Radionuclides
  57. Process by which the nucleus spontaneously emits particles and energy and transforms itself into another atom to reach stability.
    Radioactive disintegration
  58. Naturally occurring process whereby an unstable atomic nucleus relieves its instability through the emission of one or more energetic particles
    Radioactive decay
  59. Any nuclear arrangement; General term that refers to all known isotopes, both stable and unstable, of chemical chemical elements
    Nuclide
  60. The emission of particles and energy in order to become stable
    Radioactivity
  61. In addition to stable isotopes, many elements have ____; these may be artificially produced in machines such as particle accelerators or nuclear reactors.
    radioisotopes
  62. Two ways radioisotopes can decay to stability; Radioactive decay by positron emission is important for some nuclear medicine imaging.
    • beta emission
    • alpha emission
  63. An electron created in the nucleus is ejected from the nucleus with considerable kinetic energy and escapes from the atom
    beta emission
  64. Much more violent process; Alpha particle consist of two protons and two neutrons bound together; Its atomic mass number is 4
    Alpha emission
  65. What results in emission of alpha particles, beta particles, and usually gamma rays?
    Radioactive decay
  66. The rate of radioactive decay and the quantity of material present at any given time are described mathematically by a formula know as the
    Radioactive decay law
  67. From the radioactive decay law, what is this formula (T 1/2)
    half-life
  68. What radioisotopes vary from less than a second to many years. Each radioisotope has a unique, characteristic half-life?
    Half-lives
  69. Used daily in nuclear medicine and has an exact parallel in x-ray terminology
    Half-value layer
  70. 3.3 half lives =
    1 tenth life
  71. How many half-lives are required before a quantity of radioactive material has decayed to less than 1% of its original value?
    • Half-life number           Radioactivity remaining
    • 1                                    50% (half of 100%)
    • 2                                    25% (half of 50)
    • 3                                    12.5% (half of 25)
    • 4                                    6.25% (half of 12.5)
    • 5                                    3.12% (half of 6.25)
    • 6                                    1.56% (half of 3.12)
    • 7                                    0.78% (half of 1.56)
  72. Two main types of particulate radiation; Both are associated with radioactive decay.
    • alpha particles
    • beta particles
  73. Equivalent to a helium nucleus, contains 2 protons and 2 neurtons, its mass is approx 4 amu, and it carries 2 units of positive electric charge
    Alpha particle
  74. Note:
    Because of the amount of ionization, the energy of an alpha particle is quickly lost. It has a very short range in matter. Whereas in air, alpha particles can travel approx 5 cm; in soft tissue, the range may be less than 100 um
  75. An electron emitted from the nucleus of a radioactive atom; they are light particles with an atomic mass number of 0 and carry one unit of negative or positive charge.
    beta particle
  76. All ionizing radiation can be conveniently classified into two categories:
    • particulate radiation
    • electromagnetic radiation
  77. The types of radiation used in diagnostic ultrasonography and in magnetic resonance imaging are
    nonionizing radiation
  78. Depending on its energy, a beta particle may traverse ___ to ___ cm of air and approximately __ to __ cm of soft tissue.
    • 10 to 100 cm of air
    • 1 to 2 cm of soft tissue
  79. Type of rays that are forms of electromagnetic ionizing radiation
    • X-rays
    • Gamma rays
  80. X-rays and gamma rays are often called
    Photons
  81. What have no mass and no charge & they travel at the speed of light? (c = 3 x 108 m/s) and are considered energy disturbances in space.
    Photons
  82. What rays exist at the speed of light or not at all?
    • X-rays
    • Gamma rays
  83. Characteristics of Various Nuclear Arrangements (Table 2-4) page 36
  84. A method of association to help with the "iso" definitions is:
    • isotope, same proton
    • isobar, same A (Atomic Mass Number)
    • isotone, same neutron
    • isomer, metastable (all are the same)
  85. As a miniature solar system, what set the stage for the modern interpretation of the structure of matter?
    Bohr atom
  86. What is the smallest part of an element? and what is the smallest part of a compound?
    • Atom
    • Molecule
  87. Negatively charged particles that orbit the nucleus in configurations or shells held in place by electorstatic forces.
    Electrons
  88. Reaction that occur when outermost orbital electrons are shared or given up to other atoms.
    Chemical reaction
  89. Positively charged, and neutrons have no charge
    Protons
  90. What are grouped in a periodic table in order of increasing complexity; The groups on the table indicate the number of electrons in the outermost shell.
    Elements
  91. Some atoms, which contain too many or too few neutrons in the nucleus, can disinergrate, this is called
    Radioactivity
  92. What is a radioisotope is the time required for the quantity of radioactivity to be reduced to one-half its origianl value
    half-life
  93. Rays that are produced in the electron shells
    x-rays
  94. Rays that are emitted from the nucleus of a radioiosotope
    gamma rays
  95. This particle originate in the nucleus of radioactive atoms
    Beta particles
  96. The electric charge on the atom is ____
    Zero
  97. What is the smallest particle that has all the properties of an element?
    Atom
  98. What is the center of the atom?
    Nucleus
  99. particle accelerators =
    atom smashers
  100. Only the 3 primary constituents of atom, the electron, the proton,and the nuetron, are considered here. They are the ______ ______.
    fundamental particles
  101. note:
    The fundamental particles of an atom are the electron, the proton, and the neutron.
  102. _________ are very small particles that carry one unit of negative electric charge
    Electrons
  103. Because an atomic particle is extremely small, its mass is expressed in _____ _____ _____ for convienence.
    Atomic mass units (AMU)
  104. When precision is not necessary, a system of whole numbers called atomic mass _______ is used.
    numbers
  105. The atomic mass number of an electron is
    zero
  106. The nucleus contains particles called ______, of which there are 2 types: protons & neutrons. Both have nearly 2000 times the mass of the electron.
    nucleons
  107. note:
    The atom is essentially empty space
  108. The number of protons determines the _______ ______. Atoms that have the same number of protons but differ in the number of neutrons are isotopes; they behave the same way during chemical reactions.
    chemical elements
  109. Electrons can exist only in certian shells, which represent different _______ _______ _______ or energy levels.
    electron binding energies
  110. In their normal state atoms are electrically _______, the electric charge on the atoom is zero.
    neutral
  111. If an atom has an extra electron or has had an electron removed, it is said to be ________.
    ionized
  112. note
    Ionization is the removal or addition of an orbital electron from an atom.
  113. The maximum number of _______ that can exist in each shell increases with the distance of the shell from from the nucleus.
    electrons
  114. Maximum electrons per shell can be calculated by:
    2n squared
  115. NO outer shell can contain more than ____ electrons
    8
  116. _________ force; is a force theat keeps an electron in orbit
    Centipetal
  117. the force that keeps an electron in orbit is __________
    __________.
    Centripetal force
  118. The _____ _____ causes an electron to travel straight and leave the atom.
    • Centrifugal force.
    • The centrifugal force makes sure that the electrons maintain their distance from the nucleus while traveling in a circular path.
  119. The strength of attachment of an electron to the nucleus is called the _____ _____ _____.
    • electron binding energy
    • The closer an electron is to th nucleus, the more tightly it is bound. K shell elcetrons have higher binding energies than L shell electrons. L more than M and so forth
  120. Note
    The Atomic Mass number and the precise mass of an atom are not equal.
  121. Any nuclear arrangement is called a _____?
    nuclide
  122. Note:
    Radioactivity is the emission of particles and energy in order to become stable

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