Chemistry Chapter 21 Nuclear Chemistry Test Review – Flashcards
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nucleons
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protons and neutrons
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nuclide
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An atom identified by the number of protons and neutrons in its nucleus
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mass defect
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The difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons
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nuclear binding energy
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The energy released when a nucleus is formed from nucleons; a measure of the stability of a nucleus
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binding energy per nucleon
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Binding energy per nucleus divided by the number of nucleons it contains
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band of stability
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The stable nuclei cluster over a range of neutron:proton ratios (the most stable having a ration of approx. 1:1)
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nuclear shell model
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A model that nucleons exist in different energy levels (shells) in the nucleus
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magic numbers
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The numbers of nucleons that represent completed nuclear energy levels (2, 8, 20, 28, 50, 82, 126)
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nuclear reaction
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A reaction that affects the nucleus of an atom
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transmutation
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A change in the identity of a nucleus as a result of a change in the number of its protons
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radioactive decay
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The spontaneous disintegration of a nucleus into a slightly lighter nucleus, accompanied by emission of radiation, the number capture or ejection of electrons, or fission
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nuclear radiation
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Particles or electromagnetic radiation that are released from the nucleus during radioactive decay, such as neutrons, electrons, and photons
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radioactive nuclide
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An unstable nucleus that undergoes radioactive decay A nuclide that contains isotopes that decay and that emit radiation
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alpha
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Two protons and two neutrons bound together and is emitted from the nucleus during some kinds of radioactive decay (restricted almost entirely to very heavy nuclei). Sheet of paper/clothing can stop this kind of radation (least penetrating).
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4/2 He
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Alpha emission
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beta
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An electron emitted from the nucleus during some kinds of radioactive decay; neutrons can be converted to protons AND electrons; atomic number increases by one and mass number stays the same. Type of radation that can be stopped by a piece of wood
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1/0 n --> 1/1 p + 0/-1 B --> 0/-1 e (0/-1 B)
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beta emission
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positron
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A particle that has the same mass as an electron, but has a positive charge and is emitted from the nucleus during some kinds of radioactive decay; protons can be converted into neutrons; atomic number decreases by one and mass number stays the same
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1/1 p --> 1/0 n + 0/1 B --> 0/1 e (0/1 B)
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positron emission
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electron capture
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An inner orbital electron is captured by the nucleus of its own atom; inner orbital electrons converted to neutrons; atomic number decreases by one and mass number stays the same
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1/1 p + 0/-1 e --> 1/0 n
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electron capture
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gamma
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High-energy electromagnetic waves emitted from a nucleus as it changes from an excited state to a ground energy state; shorter rays than light; very dangerous in large quantities. Type of radiation that can be stopped by several inches of lead
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half-life
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The time required for half the atoms of a radioactive nuclide to decay
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given: two amounts of time
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1. time elapsed / time of half life (to find number of half-lives) 2. divide sample by 2^n, where n = number of half-lives
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given: two masses
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1. starting amount / 2^n (to find number of half-lives that have occurred) 2. a. how long does it take? half lives x time given b. what is the life life? time given / number of half lives
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decay series
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A series of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached
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parent nuclide
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A radionuclide that yields a specific daughter nuclide as a later member of a radioactive series. The heaviest nuclide of each decay series
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daughter nuclides
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The nuclides produced by the decay of another nuclides
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artificial radioactive nuclides
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Radioactive nuclides not found naturally on Earth; made by artificial transmutations
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artificial transmutations
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The transformation of atoms of one element into atoms of another element as a result of a nuclear reaction, such as bombardment with neutrons. The bombardment of nuclei with charged and uncharged particles
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transuranium elements
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Elements with more than 92 protons in their nuclei; produced by artificial transmutations
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roentgen (R)
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A unit used to measure nuclear radiation exposure; equals the amount of gamma and x-ray radiation that produces 2.58 x 10^-4 ion pairs when it passes through 1 cubic cm of dry air
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rem
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A unit measuring the dose of any type of ionizing radiation that factors in the effect that the radiation has on human tissue
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film badges
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Use exposure of film to measure the approximate radiation exposure of people working with radiation
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Geiger-Muller counters
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Instruments that detect radiation by counting electric pulses carried by gas ionized by radiation
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scintillation counters
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Instruments that convert scintillating light to an electric signal for detecting and measuring radiation
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radioactive dating
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The process by which the approximate age of an object is determined based on the amount of certain radioactive nuclides present (uses Carbon-14 to estimate the age of organic materials up to about 50,000 years old)
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radioactive tracers
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A radioactive material that is added to a substance so that its distribution can be detected later
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nuclear waste
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Product of both fission and fusion; dangerous to living organisms and needs to be contained, either via on-site storage or off-site disposal. Waste that contains radioisotopes.
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nuclear fission
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A very heavy nucleus splits into more stable nuclei of intermediate masses; can occur spontaneously or when nuclei are bombarded by particles; enormous amounts of energy released
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chain reaction
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A reaction in which the material that starts the reaction is also one of the products and can start another reaction
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critical mass
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The minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction
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nuclear reactors
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A device that uses controlled-fission chain reactions to produce energy and radioactive nuclides
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nuclear power plants
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A facility that uses heat from nuclear reactors to produce electrical energy. Uses energy as heat from nuclear reactors to produce electrical energy; five main components: shielding, fuel, control rods, moderator, and coolant.
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shielding
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A radiation-absorbing material used to decrease exposure to radiation (esp. gamma rays) from nuclear reactors
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fissile fuel
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usually Uranium-235
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coolant
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Absorbs the energy as heat that is produced in a nuclear power plant
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control rods
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Neutron-absorbing rods that help control the reaction by limiting the number of free neutrons
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moderator
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Used to slow down the fast neutrons produced in a nuclear power plant
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nuclear fusion
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Low-mass nuclei combine to form a heavier, more stable nucleus; releases even more energy per gram of fuel than fission; can be used for energy generation
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alpha, beta, and gamma
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Three main types pf radiation
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energy
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Unstable nucleus emits ________ when it decays
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alpha particle
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Ionizing radiation that consists of a helium nuclei is an ____________
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Geiger-Muller Counters Film Badges Scintillation Counters
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Detecting radiation (3 ways)
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E=mc^2
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Mass can be converted to energy, and energy to mass Energy=Mass x Speed of Light^2 Albert Einstein's equation
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gamma rays
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High energy rays
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ionizing radiation
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Not neutral and takes electrons away
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Radioactive decay or bombarding the atom
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2 ways to change the identity of a nucleus
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capture
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left side
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decay
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right side
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emission
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right side
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absorb
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left side
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strong nuclear force
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The strongest of the four fundamental forces in nature. It holds the nucleus together. The attraction of the strong nuclear force is what keeps the nucleus from flying apart.
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None of them. Although the slang term for a highly radioactive area or sample is "hot," radioactivity cannot be felt, seen, or otherwise sensed without the use of radiation-detecting instruments.
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Which of the five senses can detect radioactivity?
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It's impossible to change the rate of nuclear decay in a radioactive isotope. The rate of radioactive decay is not changed by any factors that usually affect chemical reactions, such as adding or removing heat, raising or lowering pressure, etc.
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Name one thing you can do change the rate of nuclear decay in a radioactive isotope.
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The atomic number goes up by one, which by definition means that it gains a proton and becomes a different element with a different atomic number.
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What happens to the atomic number of an element when it undergoes beta decay?
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Nothing. The mass number is the number of protons and neutrons.
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What happens to the mass number of an element when it undergoes beta decay?
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They are radioactive elements with atomic numbers greater than 92.
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When is one a radioactive element?
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Fusion must take place at extremely high temperatures
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Why is nuclear fusion considered an impractical source of energy today?
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nuclear fission reaction
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When uranium-235 splits
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True
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Two nuclei of low mass would most likely undergo nuclear fusion
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U-235
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Which uranium is most commonly used?
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True
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250 radioactive 1100 isotopes
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True
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Kidney-Thallium Thigh- Iodine Brain-Hydrogen Treat Cancer-Cobalt-60
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Nuclear Waste
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What is the one thing most people fear about?
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REM
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amount of radiation exposed to
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RAD
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amount of radiation absorbed to
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RBE
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relative biological effectiveness
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Madam Curiy
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Who discovered radiation?
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Madam Curiy
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Who discovered radium?
