Phosphorus-32 ( ⁳⁵P) is an isotope of phosphorus that undergoes radioactive decay.

1. (a)The most common isotope of phosphorus is phosphorus-31.
2. (a)(i)Describe the structure and composition of a neutral atom of phosphorus-31.[2]
3. (a)(ii)State how an atom of phosphorus-32 differs from an atom of phosphorus-31.[1]
4. (b)Phosphorus-32 decays by beta-particle emission to a stable isotope of sulfur. The half-life for this decay is 2.0 weeks.
5. (b)(i)State how a nucleus of this isotope of sulfur is different to a nucleus of phosphorus-32.[1]
6. (b)(ii)At time t=0, a radioactive sample contains 3.2 × 10¹¹ atoms of phosphorus-32. At the same moment, the sample contains no atoms of sulfur. This is shown by the cross on Fig. 6.1. On Fig. 6.1, plot a graph to show how the total number of sulfur atoms in the sample changes with t and draw a suitable curve. [Figure 6.1][3]
7. (c)State two precautions taken when storing or moving radioactive materials. 1. 2.[2]

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