JAMB Chemistry 2024 Paper

Concept:Neutron capture can increase the mass number of a nucleus while keeping the element unchanged, often creating an unstable isotope.Explanation:The nuclear reaction is: $$^{238}_{92}\mathrm{U} + ^{1}_{0}\mathrm{n} \rightarrow ^{239}_{92}\mathrm{U}$$The atomic number remains $92$, so the product is still an isotope of uranium.The mass number increases from $238$ to $239$ because the nucleus has gained one neutron.The product $^{239}_{92}\mathrm{U}$ has an unstable nucleus and will undergo radioactive decay.Therefore, the product is best described as a radioactive isotope.It is not an atomic mutation, since the process affects the nucleus, not DNA.It is not "other neutrons", because the product is a new nuclide, not neutrons.It is not simply "radiations", although radiation may be emitted when the isotope decays.Answer:B. a radioactive isotope