When bombarded by a neutron, uranium-235 undergoes fission. If the nuclides produced are xenon-139 and strontium-95, how many neutrons are emitted?

Question

Quizplus · Accepted Answer

In a typical fission reaction involving Uranium-235, two or three neutrons are usually emitted. Since the products are known to be Xenon-139 and Strontium-95, the mass number of the fission fragments adds up to 234 (139 + 95). Therefore, the total number of neutrons emitted must be 1 or 2. However, in order to sustain a chain reaction, an average of one neutron must be produced per fission, so we can assume that two neutrons were emitted in this case. Therefore, the answer is (C) 2.

When Bombarded by a Neutron, Uranium-235 Undergoes Fission