Q&A Hero

Q: Metals usually act as A) oxidizing agents. B) reducing agents. C) conjugate bases. D) conjugate acids. E) ion exchange agents.

Q: Which of the following is not a normal characteristic of a metal?A) ability to form cationsB) low ionization energyC) conductor of electricityD) high electron affinityE) malleability

Q: Which of the following exhibits the greatest metallic character? A) Ge B) Ga C) Br D) As E) All are equally metallic.

Q: Which element in Group IVA has the strongest metallic character? A) None of the elements in Group IVA is metallic. B) Pb C) Si D) C E) Ge

Q: Choose the most metallic element. A) As B) P C) Bi D) N E) Sb

Q: All of the following elements have the oxidation states listed except A) Sn2+. B) Sn+. C) Pb2+. D) Tl+. E) Tl3+.

Q: Which element commonly has both +1 and +3 oxidation states? A) Tl B) Pb C) Ba D) Al E) Cu

Q: Which of the following statements about the general properties of the main group nonmetals is incorrect? A) The oxides of nonmetals tend to be acidic. B) The ionization energies of the nonmetals increase down a group. C) Nonmetals tend to be insulators. D) Nonmetals tend to form monoatomic anions or oxoanions. E) The highest possible oxidation state for all but the most electronegative nonmetals is equal to the group number of the element.

Q: Which of the following statements about the general properties of the main group metals is not correct? A) Metallic character increases down a group. B) Metallic character decreases left to right across a period. C) The majority of main group metal oxides are acidic. D) Main group metals tend to form cations (lose electrons) in their reactions. E) Main group metal reactivity tends to increase down a group.

Q: Within a group, as the atomic numbers of the elements increase, the A) ionization energies decrease. B) atomic masses decrease. C) elements become less metallic. D) atomic radii decrease. E) electronegativities increase.

Q: Which of the following statements regarding a fission based nuclear reactor is not correct? A) A nuclear fission reactor uses the heat energy released by the fission of U-235 to produce steam. B) The control rods in a nuclear reactor contain materials which absorb neutrons. C) The moderator in a fission reactor slows down the neutrons produced from the fission of U-235. D) (heavy water), graphite, and H2O (light water) have been used as moderators in fission reactors. E) The uranium dioxide fuel pellets used in a U.S. light-water reactor are made up mostly of the U-235 isotope.

Q: It is possible that the world's energy problem could be solved by making use of the fusion reaction of deuterium and tritium. Which of the following reaction equations corresponds to that process? A) B) C) D) E)

Q: Which of the following statements is(are) true for the fission of uranium-235? A) The electron is captured by the nucleus, which becomes unstable. B) The nuclides produced are more stable than the uranium nuclide. C) The nuclides produced are individually heavier than the uranium nuclide. D) The products include neutrons. E) Two of these statements are true.

Q: Enriched uranium is uranium that has a greater proportion of A) lead-207. B) lead-208. C) deuterons. D) uranium-235. E) uranium-238.

Q: What is the nuclear binding energy per nucleon of a atom? (c=3.00x108m/s, 1amu=1.66054x10-27kg) Particle Mass (amu) 65.926036 1.00728 1.00867 0.00055 A) J/nucleonB) J/nucleonC) J/nucleonD) J/nucleonE) J/nucleon

Q: If 1 mol of oxygen-16 were formed from protons and neutrons, 0.1366 g of mass would be lost. What can best account for this loss?A) Converting from the atomic scale (in atomic mass units) to the macroscopic scale (in grams) can often cause minor errors to occur.B) The process was so exothermic that the system lost energy, which means that it also lost mass.C) This is impossible because of the law of conservation of matter (so mass must be conserved).D) When fission occurs, the nuclei remaining always have a smaller mass.E) Both a and c are correct.

Q: What is the mass defect of ? Particle Mass (amu) 11.0216 1.00728 1.00867 0.00055 A) -0.1055 amuB) -1.685 amuC) -0.0704 amuD) -4.1051 amuE) -0.1707 amu

Q: Which of the following nuclides has the highest nuclear binding energy per nucleon? A) B) C) D) E)

Q: One of the first nuclear bombs based on the fission of U-235 had a maximum yield of 7.5 x1013J. If the fission of U-235 releases 1.8 x1013J/mol, approximately what mass of U-235 was used in this bomb? (U-235 has a molar mass of 235.04 g/mol)A) 9.8 x102g U-235B) 56 g U-235C) 0.018 g U-235D) 0.0010 g U-235E) 2.3 x102g U-236

Q: Relative to the sum of the masses of its constituent nucleons (neutrons + protons), the mass of a nucleus is A) always greater. B) sometimes the same and sometimes smaller. C) always smaller. D) always the same. E) sometimes greater and sometimes smaller.

Q: What quantity of energy is released per gram of U-235 based on the following neutron induced fission of U-235? (c=3.00x108m/s)ParticleMass (amu)1.008665235.043922136.925396.910950A) 7.62 x1010J/g U-235B) 7.62 x1013J/g U-235C) 1.79 x1010J/g U-235D) 1.79 x1013J/g U-235E) 3.10 x1011J/g U-235

Q: How much energy is released when 3.00 metric tons of 2H2 gas undergoes nuclear fusion? (1metricton=1000kg, c=3.00x108m/s, 1amu=1.66054x10-27kg)2H + 2H →3He + 1n ParticleMass (amu)1.0086652.014003.01603A) JB) JC) JD) JE) J

Q: What is the energy change for the following nuclear bombardment reaction? (c=3.00x108m/s, 1 amu = 1.66054 x10-27kg, 1 MeV = 1.602 x10-13J) ParticleMass (amu)1.0086654.0026039.9640042.96115A) MeVB) MeVC) MeVD) 3.00 MeVE) MeV

Q: Metastable isotopes, such as Technetium-99m and those produced from neutron activation analysis decay by what process? A) gamma emission B) alpha emission C) beta emission D) positron emission E) all of the above

Q: Which of the following radioactive isotopes is not commonly used in medical applications?A) technetium-99mB) iodine-131C) strontium-90D) cobalt-60E) thallium-201

Q: Which of the following statements is incorrect? A) Isotope dilution is a technique used to determine the quantity of a substance in a mixture by adding a known amount of an isotope to it. B) Isotope dilution was used to elucidate the biological pathways of photosynthesis. C) Isotope dilution may be used to determine the amount of vitamin B12in food. D) A radioactive tracer is a very small amount of a radioactive isotope added to a system used to study the chemical, physical, or biological processes of a system. E) Neutron activation analysis is an analysis of elements in a sample based on the conversion of stable isotopes to radioactive isotopes by bombarding a sample with neutrons.

Q: If a tree dies and the trunk remains undisturbed for 14821 years, what percentage of original is still present? (half-life of = 5730 years) A) 33% B) 25% C) 83% D) 17%

Q: A sample of wood from an Egyptian mummy case gives a count of 8.4 cpm/g·C (counts per minute per gram of carbon). How old is the wood? (The initial decay rate of is 15.3cpm/g·C, and its half-life is 5730 years.)A) yearsB) yearsC) yearsD) yearsE) none of these

Q: Which of the following statements is(are) true of radioactive carbon-14? 1) It undergoes alpha decay. 2) It is produced in the upper atmosphere by cosmic radiation. 3) It has a constant concentration in living matter. A) 1 only B) 2 only C) 3 only D) 1 and 3 E) 2 and 3

Q: What assumption must be true for radiocarbon (14C) dating to be useful? A) 14C has the same mass as 12C. B) A constant concentration of 14C is maintained in living plants and animals through equilibration with atmospheric levels of 14C. C) The sample cannot have been chemically altered prior to the analysis. D) 14C always decays at the same rate. E) 14C is nonradioactive.

Q: A living tree contains 14C (half-life, 5730 years) and has a specific activity of 750 counts per hour. A wooden artifact recovered from an archeological site gives a count of 210 counts per hour. The age of this artifact is most nearly A) 47,000 years. B) 4,600 years. C) 11,000 years. D) 22,000 years. E) 5730 years.

Q: A radioactive isotope undergoes decay by emission of a positron. After 2.00 h, 5.880% of the initial amount of the isotope remains undecayed. What is the half-life of this isotope? A) 45.0 min B) 29.3 min C) 90.0 min D) 15.0 min E) 60.0 min

Q: The half-life of neptunium-231 is 50.0 min. How many minutes will it take for 5.0 g of this isotope to decay to 0.20 g?A) minB) minC) 1.50 x102minD) 4.00 x102 minE) min

Q: Strontium-90 is produced in nuclear explosions. It can replace calcium in the bone. The half-life of 90Sr is 27.7 years. If the activity of 90Sr in the bones of an exposed person were 90 disintegrations per second, how long would it take the activity of 90Sr to decrease to 8.1 disintegrations per second? A) 96 years B) 68 years C) 46 years D) 57 years E) 75 years

Q: A 4.50-mg sample of a newly discovered radioactive nuclide was analyzed and found to contain only 3.25 mg after a period of 31.9 h. What is the half-life of the nuclide? A) 77.3 h B) 67.9 h C) 72.2 h D) 12.8 h E) 16.8 h

Q: The half-life of phosphorus-33 is 25 days. How much of a 128-g sample will remain after 150 days? A) 2.0 g B) 16 g C) 1.0 g D) 8.0 g E) 4.0 g

Q: Iodine-131, which is used to treat thyroid cancer, has a half-life of 8.04 days. How much time is required for 84% of the isotope to decay? A) 21 days B) 7 days C) 41 days D) 53 days E) 2 days

Q: The isotope 210Pb has a half-life of 22 years. What percentage of a pure 210Pb sample prepared in April 1937 remains in April 2003?A) 13%B) 26%C) 31%D) 21%E) 38%

Q: The half-life of 42K is 12.5 h. How much will remain after 81 h if the original sample contained 256 g of 42K? A) 22 g B) 2.9 g C) 17 g D) 19 g E) 11 g

Q: The half-life of the radioisotope 158Eu is 0.77 h. How much time is required for a 160.0-g sample of 158Eu to decay to 1.29 g? A) 6.0 h B) 4.0 h C) 3.0 h D) 2.3 h E) 5.4 h

Q: The half-life of the radioactive nuclide is 9.0 min. What is the activity of a 9.8- sample of ? The molar mass of is 78.921 g/mol. (1 Ci = 3.700 x1010disintegrations/s)A) CiB) CiC) CiD) CiE) Ci

Q: What is the decay constant for a particular radioactive element that has a half-life of 5.55 years?A) 0.161/yearB) 0.113/yearC) 7.18 x10-3/hD) 25.8/sE) 0.125/year

Q: A sample of a radioactive isotope is found to have lost 39.9% of its original activity after 8.57 days. What is the decay constant of this isotope?A) 0.0594 d-1B) 0.107 d-1C) 4.36 d-1D) 0.0392 d-1E) 0.478 d-1

Q: Iodine-131 decays by beta emission with a half-life of 8.04 days. What is the decay constant for iodine-131? A) /h B) /min C) /s D) /day E) /h

Q: Use the following table to assist in answering the question below.NuclideHalf-LifeUranium-238 4.51 x109 yearsUranium-234 2.48 x105 yearsThorium-230 8.0 x104 yearsRadium-226 1.62 x103 yearsLead-210 20.4 yearsThe rate constant for the decay of unstable nuclide X by alpha-particle emission is 1.17x10-6/day. What is the identity of X?A) radium-226B) thorium-230C) uranium-238D) uranium-234E) lead-210

Q: The rate constant for the decay of a radioactive isootope is 4.226 x10-3/day. What is the half-life of of this isotope?A) 328.0 daysB) 410.0 daysC) 82.00 daysD) 164.0 daysE) none of these

Q: Consider a certain type of nucleus that has a rate constant of 2.56 x10-2min-1. Calculate the time required for the sample to decay to one-fourth of its initial value.A) 27.1 minB) 33.8 minC) 0.0512 minD) 54.1 minE) 2.56 min

Q: After 3.2 hours, of the initial amount of a particular radioactive nuclide remains unchanged. What is the half-life of the nuclide? A) 32 min B) 45 min C) 60 min D) 74 min E) 20 min

Q: What is the percent activity of a radioactive sample (relative to its original activity) that has undergone four half-lives of decay? A) 6.25% B) 25.0% C) 12.5% D) 3.13% E) 75.0%

Q: If a sample of the radioactive nuclide 139Cs has an activity of 0.0293 Ci, what is the instantaneous rate of decomposition of 139Cs in terms of grams per second? The mass of 139Cs is 138.9134 amu. (1 Ci = 3.700 x1010disintegrations/s, 1 amu = 1.66054 x10-24g)A) g/sB) g/sC) g/sD) g/sE) g/s

Q: Which of the following statements is true?A) As a radioactive isotope decays, its half-life decreases over time and its rate of disintegration remains the same.B) As a radioactive isotope decays, its half-life remains the same and its rate of disintegration remains the same.C) As a radioactive isotope decays, its half-life remains the same and its rate of disintegration increases over time.D) As a radioactive isotope decays, its half-life remains the same and its rate of disintegration decreases over time.E) As a radioactive isotope decays, its half-life decreases over time and its rate of disintegration decreases over time.

Q: Which of the following corresponds to the most rapid nuclear decay?A) t1/2= 1.0 x 103minB) t1/2= 1.0 x 109yearC) k= 1.0 x 10-3/yearD) k= 1.0 x 10-1/dayE) k= 1.0 x 10-5/s

Q: Which of the following statements concerning radioactive decay is/are correct? 1) The form of the rate law for a radioactive decay is the same as for a first-order chemical process. 2) The half-life of a radioactive sample is independent of the amount of the sample. 3) The determination of the approximate age of relics and other ancient items is limited to radiocarbon (carbon-14) dating. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: As a radioactive isotope decays, its rate constant A) remains the same. B) decreases. C) doubles. D) halves. E) increases.

Q: Which of the following types of radioactive decay has the greatest relative biological effectiveness (RBE)? A) alpha radiation B) electromagnetic radiation C) beta radiation D) gamma radiation E) neutron radiation

Q: Which of the following correctly represents the relationship among rads, rems, and relative biological effectiveness (RBE)?A) rems = rads x RBEB) rads = rems x RBEC) rads = rems x ln(RBE)D) rems = rads x RBEE) none of these

Q: Which of the following statements concerning radiation is/are correct? 1) An argon filled Geiger counter tube cannot detect neutron radiation. 2) Radiation only causes damage to biological materials. 3) The greater relative biological effectiveness of alpha radiation compared to neutron radiation means alpha radiation is more destructive to human tissue. A) 1 only B) 2 only C) 3 only D) 1 and 3 E) 2 and 3

Q: The activity of a radioactive source A) is a measure of the number of nuclear disintegrations per second. B) may be quantified in units of curies (Ci). C) is a measure of the energy released per kilogram of tissue. D) A and B E) B and C

Q: A scintillation counter measures radiation by detecting A) cations produced from radiation colliding with phosphor gases. B) electrons released when gas atoms are ionized by the radiation. C) alpha and beta particles as they strike a detector window. D) the increase in temperature when a gas is struck by radiation. E) flashes of light emitted from a phosphor affected by radiation.

Q: A Geiger counter measures radiation by detecting A) cations produced from radiation colliding with phosphor gases. B) alpha and beta particles as they strike a detector window. C) the increase in temperature when a gas is struck by radiation. D) flashes of light emitted from a phosphor affected by radiation. E) electrons released when gas atoms are ionized by the radiation.

Q: When 235U collides with one neutron, fission occurs. What is one possible set of products? A) four neutrons, , and B) four neutrons, , and C) four neutrons, , and D) four neutrons, , and E) four neutrons, , and

Q: A particular nuclear bombardment reaction is represented by the abbreviated notation . What is the identity of the nuclide X? A) B) C) D) E)

Q: The first nuclear reaction that was ever observed occurred when nitrogen-14 was bombarded with alpha particles. One product was a proton, and the other was A) . B) . C) . D) . E) .

Q: When absorbs a neutron, fission occurs. One possible fission pathway is as follows: What is the missing isotope? A) B) C) D) E)

Q: Which of these is not a transuranium element?A) plutoniumB) neptuniumC) curiumD) thoriumE) americium

Q: What is the abbreviated notation for the following nuclear bombardment reaction? A) B) C) D) E)

Q: Which of the following statements concerning nuclear bombardment and transmutation is/are correct? 1) Alpha particles emitted by natural decay processes do not have sufficient kinetic energy to penetrate and react with any nuclei. 2) Particle accelerators and other nuclear transmutation methods were a crucial component in the discovery of the lanthanide elements. 3) The discovery of new elements by bombarding other elements with high energy particles still continues to this day. A) 1 only B) 2 only C) 3 only D) 1 and 3 E) 1, 2, and 3

Q: Which of the following particles cannot be accelerated to high speeds in a particle accelerator or cyclotron? A) neutrons B) electrons C) protons D) alpha particles E) hydrogen nuclei

Q: The following reaction is an example of what type of process? A) alpha decay B) deprotonation C) fission D) transmutation E) none of these

Q: In the radioactive decay series of plutonium-244 to form lead-208, how many alpha particles and how many beta particles are emitted per plutonium atom? A) 6 alpha particles and 6 beta particles B) 3 alpha particles and 3 beta particles C) 9 alpha particles and 6 beta particles D) 12 alpha particles and 8 beta particles E) 18 alpha particles and 9 beta particles

Q: The nuclide is radioactive. When one of these atoms decays, a series of and - particle emissions occurs, taking the atom through many transformations to end up as an atom of . How many particles are emitted in converting into ?A) 6B) 2C) 214D) 8E) 4

Q: Which of the following is the most probable mode of radioactive decay for the radioactive nuclide ? A) beta emission B) gamma emission C) neutron emission D) alpha emission E) positron emission

Q: Which is the most likely mode of radioactive decay for the radioactive nuclide carbon-14? A) gamma emission B) alpha emission C) electron capture D) positron emission E) beta emission

Q: Which of the following is the most likely mode of decay for the radioactive nuclide ? A) positron emission B) gamma radiation C) beta emission D) alpha emission E) neutron emission

Q: A nucleus located to the left of the band of stability is expected to undergo what type of nuclear decay? A) alpha emission B) electron capture C) positron emission D) fission E) electron emission

Q: Which types of processes are likely when the neutron-to-proton ratio in a nucleus is too low?I decayII decayIII positron emissionIV electron captureA) III and IV onlyB) I and II onlyC) II, III, and IVD) II and IV onlyE) II and III only

Q: Nuclides with too many neutrons to be in the band of stability are most likely to decay by what mode?A) "B) fissionC) D) +E) electron capture

Q: Which particle has a +2 charge and is produced during the decay of some radioactive elements? A) alpha particle B) beta particle C) proton D) positron E) deuteron

Q: When the nucleus of an element undergoes beta emission A) the mass number increases by one. B) the mass number decreases by one. C) the atomic number decreases by one. D) the number of neutrons increases by one. E) the atomic number increases by one.

Q: A radioactive isotope decays by emission followed by two emissions. What is the change in the mass number and atomic number of the original isotope?A) The mass number decreases by 4 and the atomic number is unchanged.B) The mass number increases by 4 and the atomic number increases by 2.C) The mass number increases by 4 and the atomic number increases by 4.D) The mass number decreases by 2 and the atomic number decreases by 2.E) none of the above