Passage IV

Atomic nuclei can be represented by the combination of symbols

where Z is the number of protons in a nucleus of Element X, and A (equal to Z plus the number of neutrons) is the mass number of the same nucleus. For example, represents a nucleus of carbon containing 6 protons and 6 neutrons;represents a nucleus of a different isotope (type) of carbon that contains 6 protons and 8 neutrons.

Atomic nuclei undergo 3 types of radioactive decay. Particles emitted during the 3 types of decay are listed in Table 1. Figure 1 shows a sequence of radioactive decays, called the uranium series, that begins with the decay of .

21. A sample of spent nuclear reactor fuel contains a mixture of a uranium isotope, and a plutonium isotope, . Based on Table 1 and Figure 1, if one of the isotopes is produced by the radioactive decay of the other isotope, which of the following best explains how the mixture was formed?

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

It can be seen from figure 1 that α decay will generally reduce the proton number Z of the element by 2 and the mass number A by 4. So 23994Pu after α decay will just become 23592U