Americium-241 is a radioactive element made artificially, and it gives off $\alpha$-particles. A sample of americium-241 with mass $5.1\,\mu\text{g}$ is measured to have an activity of $5.9 \times 10^{5}\,\text{Bq}$.
(a(i))[2]
Find the number of nuclei in this americium-241 sample.
(a(ii))[2]
Find the decay constant for this americium-241 sample.
(a(iii))[2]
Find the half-life of this americium-241 sample, in years.
(b)[1]
A different radioactive element has an approximate half-life of $4$ hours. Explain why measuring the mass and activity of a sample of this element is not suitable for finding its half-life.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Number found by Avogadro relation” …