Fission definition. Nuclear Chemistry. Describe the process of nuclear fission. Search for: Nuclear Fission. Uranium 235 is a fissile isotope and its fission cross-section for thermal neutrons is about 585 barns (for 0.0253 eV neutron). Energy is absorbed or released by the process and the resulting nucleus is lighter than the combined masses of the two original nuclei added together. Nuclear fusion and nuclear fission are two different types of energy-releasing reactions in which energy is released from high-powered atomic bonds between the particles within the nucleus. For fast neutrons its fission cross-section is on the order of barns.Most of absorption reactions result in fission reaction, but a minority results in radiative capture forming 236 U. Nuclear Fission. Nuclear Fission Definition ChemistryIn the state of Texas there is a school for Advanced Nuclear Physics and Chemistry, which is called B.E. Fusion means combining lighter atomic nuclei to form a heavier nucleus. Nuclear fission is the process in which a large nucleus splits into two smaller nuclei with the release of energy. Definition of 235 U Fission – Example. Nuclear fission occurs when an atom splits into two or more smaller atoms, most often the as the result of neutron bombardment. Learning Objectives . An atom contains protons and neutrons in its central nucleus. Heterolytic fission, also known as heterolysis, is a type of bond fission in which a covalent bond between two chemical species is broken in an unequal manner, resulting in the bond pair of electrons being retained by one of the chemical species (while the other species does not retain any of the electrons from the bond pair). Fusion Definitions in Physics and Chemistry . P. C. The P stands for chemistry and the C stands for physics.So basically in nuclear physics and chemistry you are studying the two basic forces in the world, the strong force and the weak force. Binary fission is a type of asexual reproduction where a single living cell or an organelle grows twice its size and then splits into two identical daughter cells, where each of these daughter cells has the potential to grow into the size of the original cell or organelle. Key Takeaways Key Points. The main difference between these two processes is that fission is the splitting of an atom into two or more smaller ones while fusion is the fusing of two or more smaller atoms into a larger one.