Did Chadwick discover the neutron?
The answer to your question is yes. James Chadwick was an English physicist in the early 20th century. In fact, he won the Nobel Prize fo physics in 1935 for the discovery of the neutron.
The neutron was first postulated by Ernest Rutherford, an eminent nuclear physicist that Chadwick studied under early in his career. Rutherford saw that there was a discrepancy between an atom's atomic number (number of protons) and its atomic mass. He thought there might be some sort of neutral particle in the nucleus that adds to the mass but he could not prove it. Chadwick later performed a series of experiments which concluded that there were additional subatomic particles in the nucleus with the approximate mass of a proton but no electrical charge. These particles were eventually called neutrons due to their neutral charge.
The existence of a "neutral element" within the atom was suggested by Ernest Rutherford in 1920, though it was the British experimental physicist James Chadwick who discovered the neutron in 1932. Of the three fundamental particles that make up atoms, the electron, the proton and the neutron, the neutron was the last to be discovered. It's lack of a charge made it more elusive than its companions.