Questions and Answers
What does the symbol followed by ^ and a number represent?
Approximately how many of the 1500 known nuclei are stable?
1 of 6
For elements with low atomic numbers, stable nuclei have roughly equal numbers of neutrons and protons.
True
Which isotopes have a half-life similar to that of potassium-40?
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How does the ratio of neutrons to protons for stable nuclei change as atomic number increases from 1 to 82?
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The decay reaction shows how potassium-40 decays into argon. Fill in the missing mass number and atomic number for argon.
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A positron has the mass of a(n) ________, but its charge is ________.
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What is the conversion of an atom of one element to an atom of another element called?
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What are two ways transmutation can occur?
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What is half-life?
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Uranium-238 undergoes 14 transmutations before it reaches a stable isotope of what element?
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All transuranium elements are synthesized in nuclear reactors and accelerators.
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What is the half-life in years of carbon-14?
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How many years old is an artifact that contains 50% of its original carbon-14?
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What happens during the uncontrolled fission of 1 kg of uranium-235?
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What part of the reactor contains the nuclear fuel?
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What are the two parts of the reactor that control the fission reaction?
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What is the role of the coolant in a nuclear reactor?
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Where are spent fuel rods stored in a typical nuclear power plant?
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What happens to each pair of hydrogen nuclei during nuclear fusion?
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What problem has prevented the practical use of nuclear fusion?
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Why are beta particles called ionizing radiation?
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What is a device that detects flashes of light after ionizing radiation strikes a specifically coated phosphor surface called?
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How is neutron activation analysis used?
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How is radioactive iodine-131 used as a diagnostic tool?
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How many half-lives must pass for all thorium-234 atoms in a sample to decay?
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Which reactions are not affected by external factors, such as temperature and pressure?
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What are the three types of nuclear radiation?
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What determines the type of decay that occurs in a radioisotope?
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What term is used for the time it takes for half of the original radioactive material to remain?
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Transmutation can occur by bombarding the nucleus or by ________.
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In a chain reaction, what happens?
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In fusion reactions, what happens to small nuclei?
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In fission reactions, what happens to large nuclei?
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What three instruments are used to detect radiation?
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What are radioisotopes used to diagnose and treat?
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Study Notes
Nuclear Chemistry Overview
- Exponents in notation indicate powers, e.g., mass number (m#) and atomic number (a#).
- Of over 1500 known nuclei, approximately 1 in 6 are stable.
Properties of Stable Nuclei
- For elements with low atomic numbers, stable nuclei maintain a nearly equal number of neutrons and protons.
- The neutron-to-proton ratio increases from 1:1 for hydrogen to 1:5 for elements with atomic number 82.
Isotopes and Half-Life
- Potassium-40 decays into argon, with key isotopes like uranium-235 and uranium-238 sharing a similar half-life.
- The half-life of potassium-40 is 1.25 x 10^9 years; carbon-14 has a half-life of 5.730 x 10^3 years.
Transmutation and Radiation
- Transmutation can happen via fission and fusion processes.
- When potassium-40 decays, it emits beta and gamma radiation.
Nuclear Reactions
- Uncontrolled fission of uranium-235 can release energy equivalent to 20,000 tons of dynamite.
- A nuclear reactor's fuel is housed in fuel rods, which need periodic replacement.
- The reactor uses moderators to slow down neutrons and control rods to absorb them.
Nuclear Fusion and Challenges
- Hydrogen nuclei combine during nuclear fusion, producing positrons and helium while releasing energy.
- Practical use of fusion is impeded by the extreme temperatures required to initiate a reaction.
Radiation Detection and Applications
- Beta particles qualify as ionizing radiation due to their ability to remove electrons from atoms.
- Devices like scintillation counters detect radiation through light flashes caused by ionization.
- Radioactive iodine-131 is utilized in medical diagnostics for thyroid imaging.
Practical Examples and Calculations
- For manganese-56, with a half-life of 2.6 hours, only 0.0625 mg remains from an original 1.0 mg after 10.4 hours (4 half-lives).
- In 48.2 days, only 1/4 of a sample of thorium-234 remains after two half-lives, meaning not all atoms decay within that time.
Summary of Nuclear Radiation Types
- The three types of nuclear radiation are alpha, beta, and gamma.
- Nuclear reactions are unaffected by external conditions like temperature or pressure, with rates remaining constant.
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Description
This quiz covers key concepts from Chapter 25 of Pearson Chemistry, focusing on nuclear chemistry, including definitions related to exponents and atomic structure. Test your knowledge on stable nuclei and their characteristics as discussed in the chapter's sections (25.2, 25.3, 25.4).