This question is about the use of radioactivity to treat tumours in animals.
A dog has a tumour on its leg, which is about 6 millimetres deep. A vet treats the tumour using radiotherapy by injecting a radioactive isotope called phosphorus-32 into the tumour. Phosphorus-32 emits beta particles.
Phosphorus-32 is written using this symbol:
1532P ^{32}_{15}\text{P} 1532PHow many protons does a nucleus of phosphorus-32 contain?
How many neutrons does a nucleus of phosphorus-32 contain?
Phosphorus-31 is a different stable isotope of phosphorus. What are isotopes?
When phosphorus-32 decays, a beta particle is emitted and it changes into sulfur (S\text{S}S). Complete the nuclear equation by finding the missing mass number A A\,A and atomic number Z Z\,Z for the sulfur nucleus:
1532P→ ZAS+−10β− ^{32}_{15}\text{P} \rightarrow \ ^{A}_{Z}\text{S} + ^{0}_{-1}\beta^{-} 1532P→ ZAS+−10β−The tumour is about 6 millimetres deep. Explain why beta radiation is more suitable than alpha or gamma radiations for this treatment.
The energy from the beta radiation is expected to destroy the cells in the tumour over a treatment period of several weeks.
The most suitable half-life for the radioactive source would be:
Explain your choice.
