Nucleus: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Nucleus. Understanding the underlying formula is key to arriving at the correct answer below:

The fission reaction is $^{235}_{92}U + ^{1}_{0}n \rightarrow ^{89}_{36}Kr + 3(^{1}_{0}n) + ^{A}_{Z}X$. Balancing $Z$: $92 + 0 = 36 + 0 + Z \Rightarrow Z = 56$. Balancing $A$: $235 + 1 = 89 + 3 + A \Rightarrow 236 = 92 + A \Rightarrow A = 144$. The product is $^{144}_{56}Ba$.