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A radiogenic nuclide is defined as exclusively a nuclide that is itself radioactive.
Answer: False
The fundamental definition clarifies that a radiogenic nuclide is produced via radioactive decay and may be either radioactive (a radionuclide) or stable. Therefore, the assertion that it is exclusively radioactive is inaccurate.
Radiometric dating relies on measuring the ratio of a parent isotope to its stable daughter product.
Answer: False
Radiometric dating typically involves measuring the ratio of a radioactive parent isotope to its radiogenic daughter product, which may be stable or radioactive itself. The statement implies only stable daughter products are measured, which is an oversimplification.
Naturally occurring isotopes that are entirely radiogenic possess extremely long half-lives, allowing them to persist since primordial element formation.
Answer: False
Naturally occurring isotopes that are entirely radiogenic typically have half-lives too short to have persisted since primordial element formation. They are generally found as daughter products of ongoing decay processes or are continuously produced by cosmogenic processes.
Nucleogenic processes, like neutron absorption, can produce nuclides in addition to radioactive decay.
Answer: True
The text indicates that natural nuclear reactions, such as neutron absorption, referred to as nucleogenic processes, can generate nuclides distinct from those produced solely by radioactive decay.
Stable isotopes, by definition, cannot have any radiogenic component.
Answer: False
While stable isotopes are not radioactive themselves, some stable isotopes can be produced as the end product of radioactive decay chains. Therefore, they can possess a radiogenic component in addition to any primordial fraction.
The short description defines a radiogenic nuclide as a nuclide produced by nucleogenic processes.
Answer: False
The provided short description defines a radiogenic nuclide as a nuclide produced by radioactive conversion from another nuclide, not exclusively by nucleogenic processes.
A radionuclide is a type of radiogenic nuclide that is radioactive.
Answer: True
This statement accurately reflects the relationship: a radiogenic nuclide is produced by radioactive decay, and if that nuclide is itself radioactive, it is termed a radionuclide.
A nucleogenic process is defined as any nuclear reaction that results in radioactive decay.
Answer: False
A nucleogenic process is defined as a natural nuclear reaction that produces nuclides, distinct from radioactive decay itself. Neutron absorption is provided as an example.
Radiogenic nuclides are typically isolated entities and not part of sequential decay chains.
Answer: False
Many radiogenic nuclides are part of sequential decay chains, where a parent nuclide decays into a daughter nuclide, which may then decay further, eventually leading to a stable nuclide.
The 'Island of stability' refers to nuclides with extremely short half-lives that decay rapidly.
Answer: False
The 'Island of stability' is a theoretical concept in nuclear physics referring to predicted regions where atomic nuclei exhibit enhanced stability, not nuclides with extremely short half-lives.
Which of the following best defines a radiogenic nuclide?
Answer: A nuclide produced through the process of radioactive decay.
A radiogenic nuclide is fundamentally defined as any nuclide that originates from radioactive decay. It may be radioactive itself (a radionuclide) or stable.
Which of the following is NOT listed as a source of radiogenic nuclides?
Answer: Stellar nucleosynthesis
The text identifies radioactive decay and nucleogenic processes as sources of radiogenic nuclides. Cosmogenic processes are also mentioned in relation to some isotopes. Stellar nucleosynthesis, the process of element formation in stars, is not listed as a direct source of *radiogenic* nuclides in this context.
Which of the following is an example of a nuclide produced by a nucleogenic process?
Answer: A nuclide formed by natural neutron absorption.
Nucleogenic processes, such as natural neutron absorption, can produce nuclides. The other options listed are examples of nuclides primarily produced through radioactive decay.
Which statement accurately describes the relationship between a radiogenic nuclide and a radionuclide?
Answer: A radionuclide is a type of radiogenic nuclide that is radioactive.
A radiogenic nuclide is any nuclide produced by radioactive decay. A radionuclide is specifically a radiogenic nuclide that is itself radioactive. A radiogenic nuclide can also be stable.
Radiogenic nuclides are primarily used in geology for determining the composition of magma.
Answer: False
The primary geological applications of radiogenic nuclides are in radiometric dating and defining isotopic signatures, not directly for determining the composition of magma.
An isotopic signature is defined by comparing a radiogenic isotope to a non-radiogenic isotope of the same element.
Answer: True
The definition of an isotopic signature in this context involves comparing the abundance of a radiogenic isotope to that of a non-radiogenic isotope of the same element, providing characteristic information about the sample's origin or history.
The presence of excess radiogenic lead isotopes in rocks helps geologists estimate the rock's solidification time.
Answer: True
Excess amounts of radiogenic lead isotopes (206Pb, 207Pb, 208Pb) in rocks containing uranium and thorium indicate their production via radioactive decay, allowing geologists to estimate the rock's solidification age.
The 'See also' section lists concepts like 'Geoneutrino' and 'Radiometric dating'.
Answer: True
The 'See also' section indeed lists 'Geoneutrino' and 'Radiometric dating' as related concepts to radiogenic nuclides.
The excess amounts of 206Pb, 207Pb, and 208Pb in rocks help date them by indicating when the rock solidified and trapped these isotopes.
Answer: True
The measurement of excess radiogenic lead isotopes (206Pb, 207Pb, 208Pb) in rocks provides a method for geologists to estimate the rock's solidification age, as this marks the point when the isotopic clock effectively began.
The half-life of a parent nuclide is unimportant for geological dating, as long as the daughter product can be measured.
Answer: False
The half-life of a parent nuclide is critically important for geological dating, as it dictates the timescale over which decay can be measured and determines the suitability of a particular isotope system for dating materials of different ages.
An 'isotopic signature' refers to the unique elemental composition of a sample.
Answer: False
An isotopic signature refers to the relative abundance of different isotopes of an element within a sample, not its overall elemental composition. It is defined by comparing radiogenic to non-radiogenic isotopes.
What are the two principal ways radiogenic nuclides are utilized in geology, according to the text?
Answer: Radiometric dating and defining isotopic signatures.
The text explicitly states that radiogenic nuclides are primarily utilized in geology for radiometric dating and for defining isotopic signatures.
How does radiometric dating using radiogenic nuclides typically work?
Answer: By comparing the quantity of a radioactive parent isotope to its radiogenic daughter product.
Radiometric dating relies on measuring the ratio between a radioactive parent isotope and its resulting radiogenic daughter product within a sample to estimate its age.
What is the method described for defining an isotopic signature using radiogenic isotopes?
Answer: Comparing the quantity of a radiogenic isotope to a non-radiogenic isotope of the same element.
An isotopic signature is established by comparing the abundance of a radiogenic isotope to that of a non-radiogenic isotope of the same element within a sample.
What is the significance of measuring excess radiogenic lead isotopes (206Pb, 207Pb, 208Pb) in rocks?
Answer: It allows geologists to estimate the age of the rock's solidification.
Excess radiogenic lead isotopes in rocks containing uranium and thorium serve as indicators for estimating the rock's solidification age, marking the point when these isotopes became trapped.
All four stable isotopes of lead (204Pb, 206Pb, 207Pb, 208Pb) are exclusively primordial.
Answer: False
While 204Pb is exclusively primordial, the lead isotopes 206Pb, 207Pb, and 208Pb are also produced as radiogenic daughter products from the decay of uranium and thorium isotopes, meaning they are not exclusively primordial.
Lead-206 is primarily formed from the decay of Thorium-232.
Answer: False
Lead-206 (206Pb) is primarily formed from the decay of Uranium-238 (238U), not Thorium-232 (232Th), which decays to produce Lead-208 (208Pb).
Almost all atmospheric argon is primordial, with only a small fraction being radiogenic.
Answer: False
Conversely, almost all argon found in Earth's atmosphere is radiogenic, primarily Argon-40 produced from the decay of Potassium-40. Primordial argon, such as Argon-36, constitutes only a minor fraction.
Nitrogen-14 is solely produced through cosmogenic processes acting on nitrogen.
Answer: False
While cosmogenic processes contribute to nitrogen-14, some nitrogen-14 is also radiogenic, originating from the decay of Carbon-14. The Carbon-14 itself is initially formed from nitrogen-14 via cosmic ray interactions.
Radon is an element that forms in bedrock during decay, but it is not considered entirely radiogenic due to its primordial component.
Answer: False
Radon is considered entirely radiogenic because its half-life is too short for any primordial component to have survived since Earth's formation. Helium, however, does possess both primordial and radiogenic components.
Helium found in terrestrial gas wells is primarily primordial, with little contribution from radioactive decay.
Answer: False
The global supply of helium, particularly that found in terrestrial gas wells, is predominantly radiogenic. This is evidenced by a significant enrichment of radiogenic Helium-4 relative to the primordial ratio observed in these samples.
Moon rocks and meteorites are used to determine the primordial ratio of helium isotopes because they contain significant amounts of radioactive parent elements.
Answer: False
Moon rocks and meteorites are valuable for determining the primordial ratio of helium isotopes precisely because they are relatively free from Earth's atmospheric contamination and the ongoing processes that produce radiogenic helium, thus preserving the original isotopic composition.
The table of radiogenic nuclides used in geology is primarily ordered by the increasing half-life of parent isotopes.
Answer: False
The table of radiogenic isotope systems is primarily ordered by the decreasing half-life of their radioactive parent isotopes, not increasing.
Platinum-190 (190Pt) has the longest half-life among the parent nuclides listed in the table, decaying into Osmium-186 (186Os).
Answer: True
The table indicates that Platinum-190 (190Pt) possesses the longest half-life among the listed parent nuclides, approximately 483 gigayears, and decays into Osmium-186 (186Os).
Potassium-40 (40K) decays primarily to Argon-40 (40Ar) with a half-life of 11.93 gigayears.
Answer: False
While Potassium-40 (40K) has a half-life of 11.93 gigayears for its decay to Argon-40 (40Ar), this pathway accounts for only about 11% of its decays. The majority (approximately 89%) decays to Calcium-40 (40Ca).
The decay chain of Uranium-238 (238U) to Lead-206 (206Pb) takes approximately 4.468 million years.
Answer: False
The half-life of Uranium-238 (238U) for its decay chain leading to Lead-206 (206Pb) is approximately 4.468 gigayears, not million years.
Iodine-129 (129I) decays into stable Xenon-129 (129Xe) with a half-life of about 16 million years.
Answer: True
The decay of Iodine-129 (129I) into stable Xenon-129 (129Xe) occurs with a half-life of approximately 16 megayears (Myr), which is equivalent to 16 million years.
Carbon-14 (14C) has a half-life of 5730 years and decays into Nitrogen-14 (14N).
Answer: True
Carbon-14 (14C) is characterized by a half-life of 5730 years and its decay product is Nitrogen-14 (14N).
Radium-226 (226Ra) has a half-life of approximately 1600 kiloyears.
Answer: False
The half-life of Radium-226 (226Ra) is approximately 1600 years, not kiloyears.
Uranium-235 (235U) decays with a half-life of 0.7038 million years, ultimately producing Lead-207 (207Pb).
Answer: False
Uranium-235 (235U) decays with a half-life of 0.7038 gigayears (Gyr), not million years, ultimately producing Lead-207 (207Pb).
A double asterisk (**) next to a daughter nuclide in the table signifies it is a radioactive isotope.
Answer: False
A double asterisk (**) next to a daughter nuclide in the table indicates that it is an ultimate decay product within a longer decay series, not that it is radioactive.
Gigayears (Gyr) and Kiloyears (kyr) are the only units used for half-life in the table.
Answer: False
The table utilizes multiple units for half-life, including Gigayears (Gyr), Megayears (Myr), and Kiloyears (kyr), not exclusively Gyr and kyr.
Helium-3 is primarily formed through the decay of Uranium and Thorium.
Answer: False
Helium-3 (3He) is primarily considered primordial or produced from tritium decay. Helium-4 (4He) is predominantly radiogenic, formed from the decay of Uranium and Thorium.
Which of the following isotopes is cited as an example of a substance that is partly radiogenic?
Answer: Lead (specifically isotopes 206Pb, 207Pb, 208Pb)
Lead is presented as a prime example because while 204Pb is exclusively primordial, the isotopes 206Pb, 207Pb, and 208Pb are also produced radiogenically from uranium and thorium decay.
According to the text, what is the primary source of Argon-40 found in Earth's atmosphere?
Answer: Radioactive decay of Potassium-40.
The vast majority of Argon-40 in Earth's atmosphere originates from the radioactive decay of Potassium-40 within the planet's crust and mantle.
Which parent nuclide decays to produce the radiogenic isotope Lead-206 (206Pb)?
Answer: Uranium-238
The decay series of Uranium-238 (238U) ultimately leads to the formation of the radiogenic lead isotope Lead-206 (206Pb).
Which parent nuclide listed has the longest half-life mentioned in the table?
Answer: Platinum-190
According to the table, Platinum-190 (190Pt) has the longest half-life among the listed parent nuclides, measured at approximately 483 gigayears.
What is the half-life of Carbon-14 (14C) as provided in the source?
Answer: 5730 years
The source specifies that Carbon-14 (14C) has a half-life of 5730 years.
Why are extraterrestrial sources like Moon rocks and meteorites useful for studying helium isotopes?
Answer: They are free from Earth's atmospheric contamination, showing primordial ratios.
Extraterrestrial samples like Moon rocks and meteorites are valuable for determining primordial helium isotope ratios because they lack the significant radiogenic helium component found on Earth, thus preserving the original isotopic composition.
What is the half-life of Uranium-238 (238U) relevant to its decay chain producing Lead-206 (206Pb)?
Answer: 4.468 gigayears
The half-life of Uranium-238 (238U) for its decay chain leading to Lead-206 (206Pb) is approximately 4.468 gigayears.
The double asterisk (**) next to a daughter nuclide in the table signifies:
Answer: It is an ultimate decay product in a longer series.
In the context of the table, a double asterisk (**) indicates that the daughter nuclide represents the final, stable product at the end of an extended decay chain.
Which pair correctly matches a parent nuclide with its primary radiogenic daughter product mentioned in the source?
Answer: Iodine-129 -> Xenon-129
The source explicitly mentions that Iodine-129 (129I) decays into stable Xenon-129 (129Xe).
What is the primary reason the global supply of helium is considered mainly radiogenic?
Answer: Significant enrichment of radiogenic Helium-4 relative to the primordial ratio.
The predominance of radiogenic helium in the global supply is attributed to a substantial enrichment of Helium-4, originating from radioactive decay, compared to the primordial ratio of helium isotopes found on Earth.
What is the half-life of Radium-226 (226Ra) according to the table?
Answer: 1600 years
The table specifies that Radium-226 (226Ra) has a half-life of 1600 years.
An 'extinct radionuclide' is one that is still present today but has a very short half-life.
Answer: False
An extinct radionuclide is defined by its half-life being too short (typically less than 50-100 million years) for it to still exist in significant quantities on Earth today. Its past existence is inferred from the presence of its stable daughter products.
The excess of stable Xenon-129 in meteorites is evidence for the primordial existence of Iodine-129.
Answer: True
The observation of excess Xenon-129 (129Xe) in meteorites, relative to other xenon isotopes, serves as strong evidence for the prior existence of Iodine-129 (129I), an extinct radionuclide, which decayed into 129Xe.
Aluminium-26 is the only extinct radionuclide identified so far.
Answer: False
Aluminium-26 is indeed an identified extinct radionuclide, but it is not the only one. Other examples mentioned include Iodine-129 and Iron-60.
The concept of a 'primordial fraction' implies that some isotopes were formed long after the initial element formation.
Answer: False
A 'primordial fraction' refers to the amount of an isotope that was present from the very beginning of the solar system's formation and has persisted since then, not isotopes formed later.
Extinct radionuclides are detected by measuring an excess of their stable daughter products.
Answer: True
The detection or inference of extinct radionuclides relies on measuring an anomalous abundance, or excess, of their stable daughter products in geological samples, indicating their past presence and decay.
What is an 'extinct radionuclide'?
Answer: A nuclide with a half-life too short to still exist on Earth today.
An extinct radionuclide is defined by its half-life being too short for it to persist in significant quantities on Earth today. Its past existence is inferred from the presence of its decay products.
How is the existence of extinct radionuclides like Iodine-129 typically inferred?
Answer: By measuring an excess of its stable daughter product (e.g., Xenon-129).
The existence of extinct radionuclides is typically inferred by detecting an excess of their stable daughter products in geological samples, such as Xenon-129 resulting from the decay of Iodine-129.
Which of the following is NOT listed as an identified extinct radionuclide?
Answer: Magnesium-26
The text identifies Iodine-129, Iron-60, and Aluminium-26 as examples of extinct radionuclides. Magnesium-26 is mentioned as a daughter product of Aluminium-26, but not as an extinct radionuclide itself.
Radiogenic heating is the cooling effect resulting from radioactive decay.
Answer: False
Radiogenic heating refers to the thermal energy released as a consequence of radioactive decay, contributing to the internal temperature of celestial bodies, rather than a cooling effect.
Primordial heat from Earth's formation is the sole source of heat within the planet's interior.
Answer: False
The Earth's interior heat budget is derived from two primary sources: primordial heat remaining from its formation and radiogenic heating generated by the decay of radioactive isotopes within the mantle and crust.
The decay of Potassium-40 is a minor contributor to radiogenic heating in the Earth compared to Uranium and Thorium.
Answer: False
Potassium-40 (40K) decay is considered one of the primary contributors to radiogenic heating in the Earth, alongside the decay chains of Uranium-238 and Thorium-232.
Most radiogenic heating occurs in the Earth's crust, with minimal contribution from the mantle.
Answer: False
The majority of radiogenic heating occurs within the Earth's mantle and crust, where the concentrations of radioactive elements like uranium, thorium, and potassium are significant.
Radiogenic nuclides contribute significantly to Earth's internal heat budget through radiogenic heating.
Answer: True
The decay of radioactive isotopes, which produce radiogenic nuclides, is a major source of heat within the Earth, known as radiogenic heating, and significantly contributes to its internal thermal budget.
The decay of which element is the primary source of radiogenic heating within the Earth's mantle and crust?
Answer: Uranium-238, Thorium-232, and Potassium-40
The primary contributors to radiogenic heating within the Earth's mantle and crust are the decay chains of Uranium-238 and Thorium-232, along with the decay of Potassium-40.
What does the term 'radiogenic heating' refer to?
Answer: The heat generated within the Earth from the decay of radioactive isotopes.
Radiogenic heating is the phenomenon where thermal energy is released as a result of radioactive decay processes, contributing significantly to the internal temperature of celestial bodies like Earth.
What are the two main sources contributing to the internal heat of the Earth?
Answer: Primordial heat and radiogenic heating.
The internal heat of the Earth originates from two primary sources: primordial heat retained from its formation and radiogenic heating generated by the decay of radioactive isotopes.
The decay constant is irrelevant for calculating the age of geological samples using radiogenic nuclides.
Answer: False
The decay constant (λ) is a fundamental parameter in calculating the age of geological samples, as it is directly related to the half-life and represents the probability per unit time that a nucleus will undergo radioactive decay.
The 'Isotope Geology community' is responsible for establishing the consensus values for half-lives and decay constants in the table.
Answer: True
The source indicates that the consensus values for half-lives and decay constants presented in the table are derived from the 'Isotope Geology community,' signifying established scientific agreement.
The National Isotope Development Center primarily focuses on regulating the use of radioactive materials.
Answer: False
The National Isotope Development Center's role, as indicated, involves providing government supply of radionuclides, offering isotope information, and coordinating production and distribution, rather than primarily regulating radioactive materials.
The IDPRA program aims to support isotope production and related research and development.
Answer: True
The Isotope Development & Production for Research and Applications (IDPRA) program is designed to foster isotope production and support associated research and development initiatives.
What is the significance of the decay constant (λ) mentioned in the context of radiogenic nuclides?
Answer: It is the probability per unit time that a nucleus will undergo radioactive decay.
The decay constant (λ) quantifies the probability per unit time that a given atomic nucleus will undergo radioactive decay. It is inversely related to the half-life and is crucial for dating calculations.