In a nuclear reaction, the number of protons in an atom remains unchanged. The protons are the positively charged particles found in the nucleus of an atom, and they determine the atomic number and identity of the element.
Nuclear reactions involve changes in the nucleus of an atom, which can include processes like nuclear fission or nuclear fusion. In nuclear fission, a heavy nucleus is split into two or more smaller nuclei, while in nuclear fusion, two or more light nuclei combine to form a heavier nucleus.
During these processes, the number of protons in the nucleus remains constant because protons cannot be created or destroyed. The conservation of protons is a fundamental principle in nuclear reactions, as it preserves the identity of the element. However, the number of neutrons in the nucleus may change, leading to the formation of different isotopes of an element.
It's important to note that in certain nuclear reactions, such as radioactive decay, an atom can undergo a transformation where a neutron can be converted into a proton or vice versa. These types of reactions are not related to nuclear fission or fusion but rather to the spontaneous decay of unstable isotopes.