Final answer:
The mass number of an element with 83 protons and 100 neutrons is 183. Additionally, an isotope of uranium with a mass number of 235 has 92 protons and 143 neutrons.
Step-by-step explanation:
The mass number of an element is the sum of its protons and neutrons. For an element with 83 protons, 83 electrons, and 100 neutrons, the mass number can be calculated by adding the number of protons and neutrons, which is 83 + 100 = 183.
As for the example of uranium, an isotope of uranium with an atomic number of 92 (which is the number of protons) and a mass number of 235 implies that the number of neutrons is found by subtracting the number of protons from the mass number: 235 - 92 = 143 neutrons.