mostly of isotope U-238, which has 92 protons and 146 neutrons (92+146=238). Mixed with this isotope, one will find a 0.6% accumulation of U-235, which has only 143 neutrons. This isotope, unlike U-238, has atoms that can be split, thus it is extremely useful in making atomic bombs. Being that U-238 is neutron-heavy, it reflects neutrons, rather than absorbing them like its brother isotope, U-235. (U-238 serves no function in an atomic reaction, but its properties provide an excellent shield for the U-235 in a constructed bomb as a neutron reflector. This helps prevent an accidental chain reaction between the larger U-235 mass and its `bullet' counterpart within the bomb. Also note that while U-238 cannot facilitate a chain-reaction, it can be neutron-saturated to produce Plutonium (Pu-239). Plutonium can be used in place of Uranium-235 {albeit, with a different model of detonator} in an atomic bomb. Both isotopes of Uranium are naturally radioactive. Their bulky atoms disintegrate over a period of time. Given enough time, (over 100,000 years or more) Uranium will eventually lose so many particles that it will turn into the metal lead. However, this process can be accelerated. This process is known as the chain reaction. Instead of disintegrating slowly, the atoms are forcibly split by neutrons forcing their way into the nucleus. A U-235 atom is so unstable that a blow from a single neutron is enough to split it and henceforth bring on a chain reaction. This can happen even when a critical mass is present. When this chain reaction occurs, the Uranium atom splits into two smaller atoms of different elements, such as Barium and Krypton. When a U-235 atom splits, it gives off energy in the form of heat and Gamma radiation, which is the most powerful form of radioactivity and the most lethal. When this reaction occurs, the split atom will also give off two or three of its `spare' neutrons, which are not needed to make either Barium or Kryp...
