The Basics of Nuclear Reactions Learning Goal: To understand how to balance nuclear reactions and calculate...

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The Basics of Nuclear Reactions Learning Goal: To understand how to balance nuclear reactions and calculate reaction energies. A nuclear reaction is represented by an equation similar to the equation for a chemical reaction. An example of a nuclear reaction is the decay of radium into radon by the emission of an alpha particle (a helium nucleus). The equation for this reaction is 226 Ra → Rn+ He. 88 86 The superscript preceding each element indicates the nucleon number of that particular nucleus (total number of protons and neutrons). The subscript indicates the charge of the nucleus, which is equal to the atomic number for nuclei. Nuclear reactions frequently involve electrons (sometimes called beta rays) and photons (sometimes called gamma rays). Electrons, which have nucleon number 0 and charge -1, are represented in equations as either or 96 e. Photons are represented as to emphasize that they have no nucleon number and carry no charge. In nuclear reactions, several conservation laws are usually sufficient to determine the products or reactants. One of these is conservation of nucleon number. The total number of neutrons and protons in all of the reactants must be the same as the total number of protons and neutrons in the products. Although protons and neutrons sometimes change into one another, neither can simply disappear. In parts A and B consider the decay of radon by alpha particle emission: 222 Rn → X + He. Part A What is the nucleon number of the element X? Express your answer as an integer. ▸ Hints Submit ΑΣΦ ■ My Answers Give Up Part B What is the atomic number (nuclear charge) of the element X? Express your answer as an integer. ▸ Hints X ? ΑΣΦ ? nucleon number of that particular nucleus (total number of protons and neutrons). The subscript indicates the charge of the nucleus, which is equal to the atomic number for nuclei. Nuclear reactions frequently involve electrons (sometimes called beta rays) and photons (sometimes called gamma rays). Electrons, which have nucleon number 0 and charge -1, are represented in equations as either or e. Photons are represented as to emphasize that they have no nucleon number and carry no charge. In nuclear reactions, several conservation laws are usually sufficient to determine the products or reactants. One of these is conservation of nucleon number. The total number of neutrons and protons in all of the reactants must be the same as the total number of protons and neutrons in the products. Although protons and neutrons sometimes change into one another, neither can simply disappear. Another important conservation law is conservation of charge. The net charge of the reactants must be the same as that of the products. Notice that, in our equation for the decay of radium, the sum of the nucleon numbers on each side is 226 and the sum of the charges on each side is 88. If you knew everything in this equation except the isotope of radon produced, you could simply subtract 4 from 226 to find the nucleon number required to make the nucleon number of the products equal the nucleon number of the reactants. Similarly, if you knew everything in this equation except for the identity of the product element, you could simply subtract 2 from 88 and then look in a periodic table to find that the element with atomic number 86 is radon. In parts C and D consider the decay of Potassium-43 into calcium-43 via the following reaction: 43 19K Ca + X. 19¹ Part C What is the charge of the emitted particle X? Express your answer as an integer. 177 ΑΣΦΑ Submit My Answers Give Up Part D P ? Incorrect; Try Again; 4 attempts remaining This question will be shown after you complete previous question(s). previous 14 0 19 Text Part E An isotope of potassium with a half-life of roughly one billion years is often used in radioactive dating. This isotope decays through electron capture, the process of drawing an electron into the nucleus. What is the chemical symbol for the element that results from this process? The equation for the reaction is 19K+ je→?. Part E An isotope of potassium with a half-life of roughly one billion years is often used in radioactive dating. This isotope decays through electron capture, the process of drawing an electron into the nucleus. What is the chemical symbol for the element that results from this process? The equation for the reaction is e?. 10K+ Express your answer as a chemical symbol (e.g., Na for sodium). Submit My Answers Give Up Part F The reaction energy of a reaction is the amount of energy released by the reaction. It is found by determining the difference in mass between the reactants and products and then using E = mc² to convert the lost mass into the released energy. Look again at the equation for the decay of radium (Ra), given in the introduction. Use the following table of masses to determine the reaction energy of this reaction. Nucleus or particle Mass in atomic mass units radium-226 226.025402 radon-222 222.017571 alpha particle 4.002602 Express your answer in joules to three significant figures. ▸ Hints 15. ΑΣΦ ? J The Basics of Nuclear Reactions Learning Goal: To understand how to balance nuclear reactions and calculate reaction energies. A nuclear reaction is represented by an equation similar to the equation for a chemical reaction. An example of a nuclear reaction is the decay of radium into radon by the emission of an alpha particle (a helium nucleus). The equation for this reaction is 226 Ra → Rn+ He. 88 86 The superscript preceding each element indicates the nucleon number of that particular nucleus (total number of protons and neutrons). The subscript indicates the charge of the nucleus, which is equal to the atomic number for nuclei. Nuclear reactions frequently involve electrons (sometimes called beta rays) and photons (sometimes called gamma rays). Electrons, which have nucleon number 0 and charge -1, are represented in equations as either or 96 e. Photons are represented as to emphasize that they have no nucleon number and carry no charge. In nuclear reactions, several conservation laws are usually sufficient to determine the products or reactants. One of these is conservation of nucleon number. The total number of neutrons and protons in all of the reactants must be the same as the total number of protons and neutrons in the products. Although protons and neutrons sometimes change into one another, neither can simply disappear. In parts A and B consider the decay of radon by alpha particle emission: 222 Rn → X + He. Part A What is the nucleon number of the element X? Express your answer as an integer. ▸ Hints Submit ΑΣΦ ■ My Answers Give Up Part B What is the atomic number (nuclear charge) of the element X? Express your answer as an integer. ▸ Hints X ? ΑΣΦ ? nucleon number of that particular nucleus (total number of protons and neutrons). The subscript indicates the charge of the nucleus, which is equal to the atomic number for nuclei. Nuclear reactions frequently involve electrons (sometimes called beta rays) and photons (sometimes called gamma rays). Electrons, which have nucleon number 0 and charge -1, are represented in equations as either or e. Photons are represented as to emphasize that they have no nucleon number and carry no charge. In nuclear reactions, several conservation laws are usually sufficient to determine the products or reactants. One of these is conservation of nucleon number. The total number of neutrons and protons in all of the reactants must be the same as the total number of protons and neutrons in the products. Although protons and neutrons sometimes change into one another, neither can simply disappear. Another important conservation law is conservation of charge. The net charge of the reactants must be the same as that of the products. Notice that, in our equation for the decay of radium, the sum of the nucleon numbers on each side is 226 and the sum of the charges on each side is 88. If you knew everything in this equation except the isotope of radon produced, you could simply subtract 4 from 226 to find the nucleon number required to make the nucleon number of the products equal the nucleon number of the reactants. Similarly, if you knew everything in this equation except for the identity of the product element, you could simply subtract 2 from 88 and then look in a periodic table to find that the element with atomic number 86 is radon. In parts C and D consider the decay of Potassium-43 into calcium-43 via the following reaction: 43 19K Ca + X. 19¹ Part C What is the charge of the emitted particle X? Express your answer as an integer. 177 ΑΣΦΑ Submit My Answers Give Up Part D P ? Incorrect; Try Again; 4 attempts remaining This question will be shown after you complete previous question(s). previous 14 0 19 Text Part E An isotope of potassium with a half-life of roughly one billion years is often used in radioactive dating. This isotope decays through electron capture, the process of drawing an electron into the nucleus. What is the chemical symbol for the element that results from this process? The equation for the reaction is 19K+ je→?. Part E An isotope of potassium with a half-life of roughly one billion years is often used in radioactive dating. This isotope decays through electron capture, the process of drawing an electron into the nucleus. What is the chemical symbol for the element that results from this process? The equation for the reaction is e?. 10K+ Express your answer as a chemical symbol (e.g., Na for sodium). Submit My Answers Give Up Part F The reaction energy of a reaction is the amount of energy released by the reaction. It is found by determining the difference in mass between the reactants and products and then using E = mc² to convert the lost mass into the released energy. Look again at the equation for the decay of radium (Ra), given in the introduction. Use the following table of masses to determine the reaction energy of this reaction. Nucleus or particle Mass in atomic mass units radium-226 226.025402 radon-222 222.017571 alpha particle 4.002602 Express your answer in joules to three significant figures. ▸ Hints 15. ΑΣΦ ? J