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Physics for Scientists and Engineers, 6e. Chapter 44 - Nuclear Structure. Consider the following three nuclei: 12 C, 13 N, 14 O. These nuclei have the same. number of protons number of neutrons number of nucleons. The value of N = A – Z is the same for all three nuclei.

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## Physics for Scientists and Engineers, 6e

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**Physics for Scientists and Engineers, 6e**Chapter 44 - Nuclear Structure**Consider the following three nuclei: 12C, 13N, 14O. These**nuclei have the same • number of protons • number of neutrons • number of nucleons**Consider the following three nuclei: 12N, 13N, 14N. These**nuclei have the same • number of protons • number of neutrons • number of nucleons**The value of Z is the same for all three nuclei because they**are all nuclei of nitrogen.**Consider the following three nuclei: 14C, 14N, 14O. These**nuclei have the same • number of protons • number of neutrons • number of nucleons**The value of A is the same for all three nuclei, as seen by**the unchanging pre-superscript.**On your birthday, you measure the activity of a sample of**210Bi, which has a half-life of 5.01 days. The activity you measure is 1.000 μCi. What is the activity of this sample on your next birthday? • 1.000 μCi • 0 • ~ 0.2 μCi • ~ 0.01 μCi • ~ 10–22μCi**A year of 365 days is equivalent to 365 d/5.01 d ≈ 73**half-lives. Thus, the activity will be reduced after one year to approximately (1/2)73 (1.000 μCi) ~ 10–22μCi.**Suppose you have a pure radioactive material with a**half-life of T1/2. You begin with N0 undecayed nuclei of the material at t = 0. At 1/2t = T1/2, how many of the nuclei have decayed? • 1/4N0 • 1/2N0 • 3/4N0 • 0.707N0 • 0.293N0**The time we are interested in is half of a half-life. Thus,**the number of remaining nuclei is (1/2)1/2N0 = N0 / √2 = 0.707N0. The number of nuclei that have decayed is N0 – 0.707N0 = 0.293N0.**Which of the following is the correct daughter nucleus**associated with the alpha decay of ?**In alpha decay, the atomic number decreases by two and the**atomic mass number decreases by four.**Which of the following is the correct daughter nucleus**associated with the beta decay of ?**In e– decay, the atomic number increases by one and the**atomic mass number stays fixed. None of the choices is consistent with e+ decay, so we assume that the decay must be by e–.**Which of the following do you expect not to vary**substantially mong different isotopes of an element? • atomic mass number • nuclear spin magnetic moment • chemical properties**Isotopes of a given element correspond to nuclei with**different numbers of neutrons. This results in different atomic mass numbers of the nucleus—and different magnetic moments, because the neutron, despite being uncharged, has a magnetic moment. The chemical behavior, however, is governed by the electrons. All isotopes of a given element have the same number of electrons and, therefore, the same chemical behavior.

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