Nuclear Chemistry Flashcard
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band of stability
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The area on the graph within which all stable nuclei are found
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Breeder reactor
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Reactors that are able to produce more fuel then they use
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Critical mass
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The minimum mass of a sample of fissionable material necessary to sustain a nuclear chain reaction
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Electron capture
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A radioactive decay process that occurs when the nucleus of an atom draws in a surrounding electron. This captured electron combines with a proton to form a neutron
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Half-life
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the time required for one half of a radioisotopes nuclei to decay into its products
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Induced transmutation
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Induced nuclear reactions. It involves striking nuclei with high velocity charge particles
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ionizing radiation
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Radiation energetic enough to INI's matter with which it collides
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Mass defect
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The difference in mass between a nucleus and its component nucleons
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Nuclear fission
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The splitting of a nucleus into fragments.
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Nuclear fusion
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The combining of atomic nuclei
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Nucleon
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Positively charged protons and neutral neutrons within the nucleus
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Positron
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A particle with the same mass as an electron but the opposite charge
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Positron emission
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A radioactive decay process that involves the emission of a positron from a nucleus
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Radioactive decay series
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A series of nuclear reactions that begins with an unstable nucleus and results in the formation of a stable nucleus.
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Radiochemical dating
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The process of determining the age of an object by measuring the amount of a certain radioisotope remaining in that object
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Radioisotope
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Isotopes of atoms with unstable nuclei
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Radiotracer
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A radioisotope that emits non-ionizing radiation and is used to signal the presence of an element or specific substance
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Thermonuclear reaction
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Fusion reactions
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Transmutation
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The conversion of an atom of one element to an atom of another element
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Transuranium element
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Elements immediately following uranium in the periodic table. They have atomic numbers 93 and greater. all transuranium elements have been produced in the laboratory by induced transmutation and are radioactive
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Strong nuclear force
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A force that acts only on subatomic particles that are extremely close together
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X-ray
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High-energy electromagnetic radiation. they are not produced by radioactive sources. they are emitted from certain materials that are in an excited electron state
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What did the Curies contribute to the field of radioactivity and nuclear chemistry
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They discovered that the darkening of the photographic plates was due to rays emitted specifically from uranium atoms present in a mineral sample. They named such a rays radioactivity. They identified two new elements polonium and radio. 2 Nobel Prizes
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Compare and contrast chemical reactions and nuclear reactions in terms of energy changes and the particles involved
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Chemical reaction rates are greatly affected by changes in temperature pressure and concentration and also by the presence of the catalyst. Nuclear reaction rates remain constant regardless of such changes The half-life of any radioisotope is constant
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What is the difference between a positron and an electron
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a positron is positively charged and an electron is negatively charged. They have the same mass
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Describe the differences between a balanced nuclear equation and a balanced chemical equation
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In balanced chemical equations numbers and kinds of atoms are conserved. In balanced nuclear equations mass numbers and atomic numbers are conserved
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What is the strong nuclear force? On what particles does it act?
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Strong nuclear force is the force that only acts on subatomic particles that are extremely close together.
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Explain the difference between positron emission and electron capture
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During positron emission a proton in the nucleus is converted into a neutron and a positron and then the positron is he emitted The proton decreases by one and then neutrons increase by one. Like positron emission electron capture is used when the unstable nuclei lie below the band of stability. Electron capture occurs when the nucleus of an Adam draws in a surrounding electron, this captured electron combines with a proton to form a neutron. The AN decreases by 1 and an X-Ray photon is emitted.
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Explain the relationship between an atoms neutron to proton ratio and its stability
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For atoms with low atomic numbers under 20 the most stable nuclei are those with a neutron to proton ratio of 1 to 1. As atomic number increases more and more neutrons are needed to produce a strong nuclear force that is sufficient about the electrostatic repulsion forces
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What is the significance of the band of stability
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The band of stability is an area on the graph with in which all stable nuclei are found. Radioactive nuclei are found outside the band of stability and undergo decay in order to gain stability
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What is a radioactive decay series? When does the decay series end?
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A series of nuclear reactions that begins with an unstable nucleus and results in the formation of a stable nucleus. It ends when it reaches a stabilized isotope
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What scientists perform the first introduced transmutation reaction? What element was synthesized in the reaction
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Ernest Rutherford. Nitrogen 14 was bombarded with alpha particles fluorine 18 occurred and then oxygen 17 was formed
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Define transmutation. Are all nuclear reactions also transmutation reactions?
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The conversion of an atom of one element to an atom of another element. All nuclear reactions are transmutation reactions except for gamma emission.
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What are some characteristics of transuranium elements
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Atomic numbers greater than 93. Produced in a laboratory by induced transmutation.
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Carbon-14 dating makes use of specific ratio of two different radioisotopes. Define the ratio used in carbon-14 dating? why is this ratio constant in living organisms?
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The ratio used in Carbon 14 dating is Carbon 14:Carbon 12 + Carbon 13. The ratio in living organisms remains constant because organisms are constantly taking in carbon compounds that contain the same ratio of carbon-14 to Carbon 12 and Carbon 13 that is found in the atmosphere.
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Who was the first to perform an x-ray
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Wilhelm Röntgen
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Who accidentally discovered that phosphorescent uranium salts produced spontaneous omissions that darkened photographic plates
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henri becquerel
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Who discovered alpha-beta and gamma radiation while studying the effects of an electric field on the emissions of a radioactive source
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ernest rutherford
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Which of the decay processes result in a decrease neutron to proton ratio?
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beta
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Which of the decay processes result in an increase neutron to proton ratio?
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alpha, positron, electron capture
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Why is carbon-14 dating limited to objects that are approximately 24,000 years old or less
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Carbon-14 dating is limited to objects that are 24,000 years old or less because it's half-life is 5730 years
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Describe some of the current limitations of fusion as a power source
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One major problem is that fusion requires extremely high energies to initiate and sustain a reaction. The required temperature is difficult to achieve and is not practical for a controlled electrical power generation. Another significant problem is confinement of the reaction there are currently no materials capable of withstanding the tremendous temperatures that are required for a fusion reaction
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Describe some of the problems of using fission as a power source
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One problem with using fission as a power source is the hazardous radioactive fuels and the fission products that can't be recycled so must be stored as nuclear waste. Limited amounts of Uranium available.
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What is a chain reaction? Give an example of a nuclear chain reaction
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A chain reaction is when one reaction causes more reactions to occur An example would be an atomic bomb
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How is binding energy per nucleon related to mass number
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Binding energy per nucleon reaches a maximum around the mass number of 60. Lower mass numbers have a lower binding energies
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Explain how binding energy per nucleon is related to fission and fusion reactions
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In nuclear fission atoms with a mass number greater than 60 often split into smaller atoms to increase their stability.
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Discuss how the amount of fissionable material present effects the likelihood of a chain reaction
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The more fissionable material that is present the more likely a chain reaction is to occur. This is because the neutrons have a better chance of hitting the material if there is more present
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Explain the purpose of control rods in a nuclear reactor
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The purpose of the control rods is to keep the chain reaction from going out of control. The control rods absorb virtually all of the neutrons produced in the reaction
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Why were breeder reactors developed
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Breeder reactors were developed so that less uranium would need to be used in a fission reaction
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Why does nuclear fusion require so much heat? How is heat contained within a TokaMac reactor
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because nuclear fusion reactions require immense amount of energy that can only be achieved an extremely high temperatures. The Tokamac reactor uses strong magnetic field to contain the heat of a fusion reaction
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What is ionizing radiation
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Radiation energetic enough to ionized the matter with which it collides
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What is the difference between somatic and genetic damage
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Somatic damage only affects non-reproductive body tissue and therefore affects the organism only during its own lifetime. Genetic damage can affect the offspring because it damages reproductive tissue which may affect genes and chromosomes in the sperm and eggs of the organism
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What property of isotopes allows radiotracers to be useful in studying chemical reactions
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The fact that all of an element isotopes have the same chemical properties makes to use of radioisotopes useful in studying chemical reactions
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List several applications that involve phosphors
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Phosphors are often used for things that need to glow-in-the-dark for example the numbers on a watch TV screens or computer screens
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Explain how a Geiger counter measures levels of ionizing radiation present
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The geiger counter works when ionizing radiation penetrates into the tube and the gas inside the tube absorbs its radiation and becomes ionized. The ionized gas contains ions and free electrons which are attracted to the wire causing a current to flow
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What information about an atom can you use to predict whether or not it will be radioactive
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If an atom has an atomic number larger than 93 then it is radioactive
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Describe the penetration power of alpha beta and gamma radiation
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