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Nuclear medicine uses radiopharmaceuticals for disease treatment and as tracers in medical imaging studies. Yttrium-90 (⁹⁰Y) is a radiopharmaceutical agent used to treat overgrown joint lining known as pigmented villonodular synovitis, as well as some forms of liver cancer. It has a half-life of about 64 hours.Although the relatively short half-life of ⁹⁰Y is optimal for use in medical applications, transportation and storage of the radiopharmaceutical are not feasible. As a result, strontium-90 (⁹⁰Sr) , with a half-life of 28.8 years, is the most common source of ⁹⁰Y. ⁹⁰Sr is created by a nuclear fission process that begins with uranium-235 (²³⁵U) in a nuclear reactor as shown in Reaction 1.²³⁵U → ⁹⁰Sr + ZReaction 1Fission of ²³⁵U produces ⁹⁰Sr as well as additional fission products (Z) including, but not limited to, technetium-99 (⁹⁹Tc) , iodine-129 (¹²⁹I) , and zirconium-93 (⁹³Zr) . Figure 1 shows the distribution of fission products.
Figure 1 Distribution of ²³⁵U fission products by atomic weightTo create the final ⁹⁰Y required for nuclear medicine studies, ⁹⁰Sr decay is carried out in a controlled ⁹⁰Y generator. ⁹⁰Y is then separated from residual ⁹⁰Sr for use in clinical applications.
Adapted from Wheeler CE. Comments on vaccines, August 1987. J Am Acad Dermatol. 1988;18(1 Pt 2) :232-4.
-⁹⁰Y converts to ⁹⁰Zr by beta decay. Which of the following elements exhibits chemical properties most similar to zirconium-90? (Note: Assume that ⁹⁰Zr gains any needed valence electrons from its environment immediately after being formed by the nuclear conversion.)

Question

Passage
Nuclear medicine uses radiopharmaceuticals for disease treatment and as tracers in medical imaging studies. Yttrium-90 (⁹⁰Y) is a radiopharmaceutical agent used to treat overgrown joint lining known as pigmented villonodular synovitis, as well as some forms of liver cancer. It has a half-life of about 64 hours.Although the relatively short half-life of ⁹⁰Y is optimal for use in medical applications, transportation and storage of the radiopharmaceutical are not feasible. As a result, strontium-90 (⁹⁰Sr) , with a half-life of 28.8 years, is the most common source of ⁹⁰Y. ⁹⁰Sr is created by a nuclear fission process that begins with uranium-235 (²³⁵U) in a nuclear reactor as shown in Reaction 1.²³⁵U → ⁹⁰Sr + ZReaction 1Fission of ²³⁵U produces ⁹⁰Sr as well as additional fission products (Z) including, but not limited to, technetium-99 (⁹⁹Tc) , iodine-129 (¹²⁹I) , and zirconium-93 (⁹³Zr) . Figure 1 shows the distribution of fission products.

Passage Nuclear medicine uses radiopharmaceuticals for disease treatment and as tracers in medical imaging studies. Yttrium-90 (<sup>90</sup>Y) is a radiopharmaceutical agent used to treat overgrown joint lining known as pigmented villonodular synovitis, as well as some forms of liver cancer. It has a half-life of about 64 hours.Although the relatively short half-life of <sup>90</sup>Y is optimal for use in medical applications, transportation and storage of the radiopharmaceutical are not feasible. As a result, strontium-90 (<sup>90</sup>Sr) , with a half-life of 28.8 years, is the most common source of <sup>90</sup>Y. <sup>90</sup>Sr is created by a nuclear fission process that begins with uranium-235 (<sup>235</sup>U) in a nuclear reactor as shown in Reaction 1.<sup>235</sup>U → <sup>90</sup>Sr + Z<strong>Reaction 1</strong>Fission of <sup>235</sup>U produces <sup>90</sup>Sr as well as additional fission products (Z) including, but not limited to, technetium-99 (<sup>99</sup>Tc) , iodine-129 (<sup>129</sup>I) , and zirconium-93 (<sup>93</sup>Zr) . Figure 1 shows the distribution of fission products. <strong>Figure 1</strong> Distribution of <sup>235</sup>U fission products by atomic weightTo create the final <sup>90</sup>Y required for nuclear medicine studies, <sup>90</sup>Sr decay is carried out in a controlled <sup>90</sup>Y generator. <sup>90</sup>Y is then separated from residual <sup>90</sup>Sr for use in clinical applications. Adapted from Wheeler CE. Comments on vaccines, August 1987. J Am Acad Dermatol. 1988;18(1 Pt 2) :232-4. -<sup>90</sup>Y converts to <sup>90</sup>Zr by beta decay. Which of the following elements exhibits chemical properties most similar to zirconium-90? (Note: Assume that <sup>90</sup>Zr gains any needed valence electrons from its environment immediately after being formed by the nuclear conversion.) A) <sup>90</sup>Nb B) <sup>174</sup>Hf C) <sup>46</sup>Sc D) <sup>48</sup>Ca

Figure 1 Distribution of ²³⁵U fission products by atomic weightTo create the final ⁹⁰Y required for nuclear medicine studies, ⁹⁰Sr decay is carried out in a controlled ⁹⁰Y generator. ⁹⁰Y is then separated from residual ⁹⁰Sr for use in clinical applications.
Adapted from Wheeler CE. Comments on vaccines, August 1987. J Am Acad Dermatol. 1988;18(1 Pt 2) :232-4.
-⁹⁰Y converts to ⁹⁰Zr by beta decay. Which of the following elements exhibits chemical properties most similar to zirconium-90? (Note: Assume that ⁹⁰Zr gains any needed valence electrons from its environment immediately after being formed by the nuclear conversion.)

Quizplus · Accepted Answer

11ecba2d_1188_df75_a3bf_fbf9f47ebdcd_MD0008_00 Atoms are most stable when they have a full outer (valence) orbital shell. For this reason, the chemical behavior of an atom is determined largely by the configuration of electrons in its valence shell, as this number determines how many electrons must be gained or lost to achieve stability. Elements in the same column of the periodic table have the same configuration of valence electrons, and therefore have similar chemical properties. ⁹⁰Y decays by emitting a nuclear electron, which causes an increase in the atomic number and produces zirconium-90 (⁹⁰Zr). Zirconium is in the same column as hafnium (Hf), and therefore any isotope of hafnium will have similar chemical properties to any isotope of zirconium. (Choice A) Niobium-90 (⁹⁰Nb) is in the same row as ⁹⁰Zr, and has the same atomic mass. However, elements in the same row of the periodic table have different numbers of valence electrons, and therefore have different chemical properties. (Choice C) Scandium-46 (⁴⁶Sc) is in the same column as ⁹⁰Y. It would have similar chemical characteristics before, but not after, electron emission. (Choice D) Calcium-48 (⁴⁸Ca) is in the same column as ⁹⁰Sr. If ⁹⁰Y decayed by positron emission instead of electron emission, this would be the correct answer. Educational objective: Chemical behavior is governed largely by the number of electrons in an atom's valence shell. Atoms with the same number of valence electrons (same column of the periodic table) have similar chemical properties.

Passage Nuclear Medicine Uses Radiopharmaceuticals for Disease Treatment and as Tracers