Uranium-235 undergoes nuclear fission as shown in the diagram below. (}_{56)^139Ba 235 O^n 92 n 200 MeV O^n x Which element does X represent?

To determine the element represented by in the nuclear fission reaction, we need to follow the steps of the reaction as described in the picture details and use the periodic table to identify the elements based on their atomic numbers.Step 1: Uranium-235 captures a neutron to become Uranium-236.- Uranium (U) has an atomic number of 92 (92 protons).Step 2: Uranium-236 emits a neutron and a proton to become Neptunium-237.- Emitting a proton means the atomic number decreases by 1 (since a proton has been lost).- Neptunium (Np) has an atomic number of 93 (92 - 1 = 91).Step 3: Neptunium-237 captures a neutron to become Uranium-238.- Capturing a neutron does not change the atomic number, only the mass number.- Uranium is back in the picture with an atomic number of 92.Step 4: Uranium-238 emits a proton and a neutron to become Barium-239.- Emitting a proton again decreases the atomic number by 1.- Barium (Ba) has an atomic number of 56 (92 - 1 = 91, but since we are now at Barium, we must have made a mistake in the previous step. Neptunium should have an atomic number of 93, so when it loses a proton, it becomes Uranium with an atomic number of 92. Now, when Uranium-238 loses a proton, it becomes element 91, which is Protactinium (Pa), not Barium).Step 5: Protactinium-239 emits a proton and a neutron to become element with an atomic number of 240.- Emitting a proton decreases the atomic number by 1.- Therefore, the atomic number of is 90, which corresponds to Thorium (Th).Final Answer: Element represents Thorium (Th).