a) What is ionising radiation? (1 mark) b) Why is ionising radiation dangerous to living tissue? (1 mark) c) Why is alpha radiation particularly dangerous if ingested? (1 mark) (Marks available: 3) The radioactive nuclide, 23992U, decays by alpha-particle emission. The newly formed nuclide X is also unstable and decays by a different radioactive emission to a third nuclide Y. Y then decays to become another isotope of uranium 23492U. a) Explain the meaning of the term isotope. (1 mark) b) Write down suitable symbols in the form 23992U for an α-particle ...................... a β-particle.......................... (2 marks) c) Show how 23992U can become the isotope 23492U after three decays. (3 marks) (Marks available: 6) The equation shows a possible neutron-induced fission for a nucleus of plutonium-239. How many neutrons are emitted? number of neutrons = ................... (1 mark) Answer Answer outline and marking scheme for question: a) Radiation capable of ionising atoms. (1 mark) b) The charged particles/ions produced can interfere with biological processes. (1 mark) c) Alpha radiation is highly ionising if inside the body it can easily damage internal tissue. (1 mark) (Marks available: 3) a) An element can exist in more than one form, having a different number of neutrons /can have different mass but same proton number / AW (1 mark) b) 42He / 42α ; (-) 0-1e / 0-1β (2 marks) c) 23892U →23492U + 42α + 0-1β + 0-1β or 23892U→ 23490X + 42α 23490X→ 23491Y + 0-1β 23491Y→23492U + 0-1β (3 marks) (Marks available: 6) Six (1 mark)