The Curiosity rover sent to explore the surface of Mars has an electric generator powered by heat from the radioactive decay of 238Pu, a plutonlum isotope that decays by alpha emission with a halflife of 88 years. At the start of the mission, the generator contained 9.6×1024 nuclel of 238Pu. What is the daughter nucleus of the decay? 236Th 238Am 234U 238Pu 238Np
Answer
Understanding the Alpha Decay of Plutonium-238
The Curiosity rover uses a radioisotope thermoelectric generator (RTG) powered by the alpha decay of 238Pu (Plutonium-238). Alpha decay is a type of radioactive decay in which an unstable nucleus emits an alpha particle (2 protons and 2 neutrons), which is essentially a helium-4 nucleus (4He or α).
Decay Equation:
238Pu → 234U + 4He
- Atomic Number of Plutonium (Pu): 94
- Atomic Number of Helium (He): 2
- Atomic Number of Daughter: 94 – 2 = 92 → Uranium (U)
- Mass Number of Daughter: 238 – 4 = 234
So, the daughter nucleus formed is 234U (Uranium-234).
Final Answer: Uranium-234 (234U)
This process generates a consistent heat output which is converted into electricity, making it ideal for long-duration space missions like Mars exploration.