(a)[2]
Complete the key in Fig. 12.1. State the names of the particles shown.
(b)[2]
For each isotope, place the number of protons and the number of neutrons in the correct table positions.
(c(i))[1]
Describe the ability of $\alpha$-particles to penetrate matter.
(c(ii))[2]
Explain why swallowing a source that emits $\alpha$-particles is dangerous.