Two neutral atoms are atoms of different isotopes of the same element.

1. (a)(i)State one similarity in the structures of these two atoms,[1]
2. (a)(ii)one difference between the structures of these two atoms.[1]
3. (b)(i)The isotope plutonium-239 decays by the emission of an alpha-particle (symbol α) to an isotope of uranium (symbol U). The half-life for this decay is 2.4 × 10⁴ years. Complete the equation for this decay. 239 Pu 94 → .................... U + .................... α[3]
4. (b)(ii)The count rate measured due to a pure sample of plutonium-239 is 6400 counts/second. Calculate the count rate after a period of 1.2 × 10⁵ years has elapsed. count rate = [3]
5. (b)(iii) 1.Fig. 10.1 shows an alpha-particle entering a uniform magnetic field. [Figure 10.1] On Fig. 10.1, draw the path of the alpha-particle in the magnetic field.[2]
6. (b)(iii) 2.Explain why the alpha-particle follows the path you drew in (b)(iii)1.[1]
7. (c)(i)In a nuclear reactor at a power station, plutonium-239 is made to undergo nuclear fission. State what is meant by nuclear fission.[1]
8. (c)(ii)State what happens to a plutonium-239 nucleus in the nuclear reactor to cause fission.[1]
9. (c)(iii) 1.State one advantage of generating electricity in a nuclear power station rather than using an oil-fired power station,[1]
10. (c)(iii) 2.an array of wind turbines.[1]

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