Part I - Radiation Physics - The Structure of Things
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johnthomas75 Plus on November 25, 2011
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Page 1 - 13 of Ekstrands Physics for Residents
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Radiation Physics - Wake Forest
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34 terms
Terms | Definitions |
|---|---|
 Atoms consist of a positivelycharged nucleus, approximately _____ in diameter | 10^-13 cm |
| Electrons are negatively charged particles occupying orbitals whose size is approximately _____ in diameter | 10-8 cm. |
| Each orbital in an atom has a specific energy of interaction associated with it, the ________ , and a discrete level called a _____________ | binding energy energy quantum number n (n = 1,2,3 . . .). |
| The smaller the number n of an energy quantum number, the higher/lower is the binding energy (the more/less tightly the electron is bound to the nucleus). | Lower, More |
| Energy Quantum numbers have additional energy subdivisions determined by ________ referred to by the designation_____ each with ___ ____. These impact the energy of the orbiting electron and the ____ of the orbital | angular momentum opposite spins l, ml Shape |
| How many electrons occupy each orbital? | 2 |
| The group of orbitals having the same energy quantum number (and therefore approximately the same binding energy) is called a ______. The lowest energy shell (n=1) is called the __ ____. Next is the __ _____ (n=2), then come M, N, etc. | The group of orbitals having the same energy quantum number (and therefore approximately the same binding energy) is called a shell. The lowest energy shell (n=1) is called the K shell. Next is the L shell (n=2), then come M, N, etc. |
| binding energies are +/- numbers, with the lowest level being the smallest/greatest in absolute magnitude. The unit of binding energy is ____ an electron w/a binding energy of 0 is _____ | - greatest eV just barely free of an atom |
| One eV is the amount ________ | One eV is the amount of energy an electron gains in crossing a potential difference of 1 volt (e.g., from a 1 volt battery). |
| Hydrogen is the simplest of atoms, having ____ electron orbiting the nucleus. | Hydrogen is the simplest of atoms, having only one electron orbiting the nucleus. |
| For atoms with many electrons, each shell with an energy quantum number n can have a maximum of ____ electrons. | 2n^2 For example, the L shell can have 8 electrons, the M shell can have 18, etc. The lowest energy levels are always filled first. |
| Ionization physically means | That an energy sufficient to remove an electron from an atom has been supplied resulting in an ejected electron and a positively charged ion |
| If an electron jumps from a higher energy level to a lower one (_______ or _________), the atom gives off the excess energy, frequently in the form of _________ _________ | If an electron jumps from a higher energy level to a lower one (de-excitation or relaxation), the atom gives off the excess energy, frequently in the form of electromagnetic radiation. |
| In free space the velocity of all electromagnetic (em) radiation is____, designated as __. ___ = 3 x 10^8 meter/second. | In free space the velocity of all electromagnetic (em) radiation is a constant, c. c = 3 x 108 meter/second. |
| The wavelength and frequency of the wave are directly/inversely proportional to one another | inversely |
| Quantum theory asserts that all em radiation is transmitted in discrete energy units called _____ or _____. The energy of an individual photon is related to the wave frequency according to E = ______ | Quantum theory asserts that all em radiation is transmitted in discrete energy units called quanta or photons. The energy of an individual photon is related to the wave frequency according to E = hv or E = hc/λ h = 4.14x10^-15 ev/sec |
| For X rays, wavelength is in units of ____, and the relationship of E (KeV) = ________ | E (KeV) = 12.4/λ (angstroms) |
| A free radical is a molecule (usually electrically neutral) with an ___ ____. A free radical is very reactive chemically and usually has a long/short half life, but is shorter/longer lived than an ion. Free radicals are produced by ionizing radiation. | A free radical is a molecule (usually electrically neutral) with an unpaired electron. A free radical is very reactive chemically and usually has a short half life, but is longer lived than an ion. Free radicals are produced by ionizing radiation. |
| A nuclide (= _______ ) is represented by: A Z X where: X = Chemical symbol A = Z = | species of atom with a specific number of neutrons and protons X is the chemical symbol A is the atomic mass number (the number of neutrons + protons) Z is the atomic number (the number of protons) |
| As Z increases, the K shell binding energy increases in proportion to ____ | As Z increases, the K shell binding energy increases in proportion to Z^2 |
| If an atom with a high Z is excited by an high energy (external) electron, a vacancy can be created in the K or L shell. An outer electron will fill the vacancy and a photon with energy in the X-ray region is created. The photon energy is equal to the difference of the two energy levels and is characteristic of the particular atomic species involved (hence the designation) The X ray created from that atom is called ______ and is specific to that type of atom | Characteristic X-rays If an atom with a high Z is excited by an high energy (external) electron, a vacancy can be created in the K or L shell. An outer electron will fill the vacancy and a photon with energy in the X-ray region is created. The photon energy is equal to the difference of the two energy levels and is characteristic of the particular atomic species involved (hence the designation) |
| Isobars - | nuclides with the same A but different Z, isob"a"r = same "a"tomic number e.g., 27 Co 60 and 28 Ni. 60 |
| Isotopes - | nuclides with the same Z (protons) but different A. Isoto"p"e = same "p"roton # (These atoms are chemically the same but may have different nuclear properties), e.g., 8 O 16 and 8 O 15 |
| Isotones - | same number of neutrons (A - Z) but different Z, e.g., Isoto"n"es = Same "n"eutron # 13 Al 27 and 14 Si 28 |
| Isomers - | same A, same Z, but different internal nuclear energy, different configuration of the neutrons and the protons, e.g., 43 99Tc and 43 99mTc |
| Because the mass of an atom is so small, we frequently measure it in units other than kilograms. One unit is the_______, is set to equal _________ which has a mass number A = 12 (6 protons and 6 neutrons). In more common units 1 = | atomic mass unit, AMU 1/12 of a carbon atom 1amu=1.66 x 10-27 kg. |
| If E = mc^2 and mass is in AMU then Energy (MeV) = _____ | Energy(MeV) = 931 x mass(AMU) e.g. Mass (AMU) Mass (MeV) Electron 0.00055 0.51 Proton 1.00727 938 Neutron 1.00866 939 |
| energy that is released when the particles which were bound together are disrupted = | Nuclear Binding Energy |
| For light nuclides (Z < 20), the most stable configuration occurs when the number of neutrons is approximately less than/greater than/equal to the number of protons For heavier nuclides, stability occurs when the number of neutrons is less than/greater than/equal to the number of protons. | For light nuclides (Z < 20), the most stable configuration occurs when the number of neutrons is approximately equal to the number of protons. For heavier nuclides, stability occurs when the number of neutrons is greater than the number of protons. |
| Nuclides in which A is an even/odd number and A - Z is also an even/odd number tend to be most stable. | Nuclides in which A is an even number and A - Z is also an even number tend to be most stable. |
| In terms of evenness of the numbers, the stability varies as follows: Proton # Neutron # Most stable __ ____ Equally ___ ___ stable ___ ____ Least stable ___ ___ Bismuth (Z = 83) is the stable nuclide with the highest Z. | In terms of evenness of the numbers, the stability varies as follows: Proton # Neutron # Most stable even even Equally even odd stable odd even Least stable odd odd Bismuth (Z = 83) is the stable nuclide with the highest Z. |
| What are the 4 fundamental forces known in nature according to strength | Gravitation<weak nuclear<electric/magnetic<strong nuclear |
| beta decay is which type of the fundamental forces of nature | weak nuclear force |
| What does the "mass defect" seen in atoms like deuterium represent | binding energy of the nucleus |
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