Here's why:
* Nuclear Reactions: The reaction you provided is a nuclear reaction, specifically nuclear fission. Nuclear reactions involve changes within the nucleus of an atom.
* Nucleus Components: The nucleus contains protons and neutrons, which are collectively known as nucleons.
* Fission Process: In fission, a neutron strikes the nucleus of a heavy atom (like Uranium-235). This causes the nucleus to become unstable and split into two or more lighter nuclei (in this case, Xenon-134 and Strontium-100) along with the release of energy and additional neutrons.
Therefore, the neutrons involved in the reaction are interacting directly with the nucleus of the Uranium-235 atom, leading to the fission process.
