Uranium-235 is used instead of uranium-238 because it is more easily fissionable, meaning it can sustain a chain reaction in a nuclear reactor. Uranium-235 has a higher probability of undergoing fission when struck by a neutron compared to uranium-238. This makes it more efficient for generating nuclear energy. Additionally, uranium-235 has a lower critical mass, which means less material is needed to sustain a chain reaction, making it more practical for use in nuclear reactors. **

The main difference between Uranium-238 and Uranium-235 is their atomic mass. Uranium-238 has 146 neutrons and Uranium-235 has 143 neutrons. This small difference in the number of neutrons results in different nuclear properties. Uranium-235 is the isotope used for nuclear fuel and weapons because it is fissile, meaning it can sustain a nuclear chain reaction, while Uranium-238 is not fissile but can be used as fertile material to produce fissile isotopes like Plutonium-239. **

Uranium-235 and uranium-238 are isotopes of the element uranium. Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. Uranium-235 has 92 protons and 143 neutrons, while uranium-238 has 92 protons and 146 neutrons. Both isotopes are radioactive and are used in nuclear reactors and weapons. **

When Uranium-235 undergoes fission, it produces a variety of fission products. These products can include isotopes of elements such as xenon, strontium, cesium, iodine, and barium, among others. These fission products are radioactive and can pose a hazard if not properly contained and managed. They are a key consideration in the design and operation of nuclear reactors and in the handling and disposal of nuclear waste. **

Iodine-131 is pronounced as "eye-oh-dine one-thirty-one", Strontium-90 is pronounced as "stron-tee-um ninety", and Uranium-235 is pronounced as "yoo-rain-ee-um two-thirty-five". **

The term "fuel" is not suitable for Uranium 235 because it does not undergo combustion like traditional fuels such as gasoline or coal. Uranium 235 is used as a fuel in nuclear reactors where it undergoes nuclear fission to produce energy. This process is very different from the chemical reactions that occur when traditional fuels are burned. Therefore, it is more accurate to refer to Uranium 235 as a nuclear fuel rather than simply a fuel. **

Red and black dots in uranium-235 nuclei represent the distribution of neutrons and protons within the nucleus. Red dots typically represent protons, while black dots represent neutrons. In uranium-235, there are 92 protons and 143 neutrons, so the red and black dots would be arranged accordingly to reflect this composition. This visualization helps to understand the structure and stability of the nucleus. **

The one neutron needed to split uranium-235 in a nuclear fission reaction can come from a variety of sources. In a nuclear reactor, the neutron can be provided by other fission reactions occurring within the reactor core. Alternatively, the neutron can be introduced into the uranium-235 through a process called neutron bombardment, where neutrons are intentionally directed at the uranium-235 to induce fission. Overall, the neutron needed to split uranium-235 can be generated within the reactor itself or introduced from an external source. **