james chadwick discovered evidence of what part of an atom? give the full name, not an abbreviation.

James Chadwick discovered evidence of the neutron part of an atom. The neutron is a particle with no electric charge that, along with positively charged protons, makes up the nucleus of an atom. Chadwick's discovery of the neutron was a pivotal moment in nuclear physics and was recognized with the Nobel Prize in Physics in 1935.