Final answer:
The nuclear equation for the alpha decay of Californium-251 is 251Cf → 247Cm + 4He, resulting in the formation of Curium-247 as the daughter isotope.
Step-by-step explanation:
The student asked to write the nuclear equation for the decay of Californium-251 undergoing alpha decay. Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and transforms into a new element. The alpha particle is comprised of 2 protons and 2 neutrons, which is essentially a helium-4 nucleus.
For Californium-251 (251Cf), the alpha decay process can be represented by the following nuclear equation:
251Cf → 247Cm + 4He
Through this process, Californium-251, which has an atomic number of 98, decays to form Curium-247 (Cm), the daughter isotope, with an atomic number of 96 because it has lost two protons in the form of an alpha particle.