(a)[1]
Explain why hydrogen-3 is unable to decay by alpha-particle emission.
(b(i))[3]
Hydrogen-3 decays by beta emission to produce an isotope of a different element. In the equation, that element is labelled Q. Complete the nuclide equation for the decay of hydrogen-3: $^{3}_{1}\text{H} \rightarrow \; \beta + \; Q$.
(b(ii))[1]
State the name of the element denoted by Q.
(c(i))[2]
Hydrogen-3 has a half-life of 12 years. Define ‘half-life’.
(c(ii))[1]
A sample of hydrogen-3 is kept on a laboratory bench beside a Geiger-Müller tube and counter. The count rate is measured at the same time on four consecutive days. Table 8.1 gives the count rates obtained. State why the count rate decreases and increases.