Answer: Thus X is Plutonium
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
General representation of alpha decay :
where Z = atomic number
A= mass number
X and Y = atomic symbol of elements
Thus
Thus X is Plutonium with atomic number 94 and mass number 239