Atom bombardment ejects what appeared to be hydrogen nuclei. By 1920 he had accepted that the hydrogen nucleus is a distinct particle within the atom and named it proton. Neutrons have no electrical charge and have a free mass of 1,839 times the mass of the electron, or , the heaviest of the three constituent particles, but it can be reduced by the nuclear binding energy. Neutrons and protons (collectively known as nucleons) have comparable dimensions—on the order of —although the 'surface' of these particles is not sharply defined. The neutron was discovered in 1932 by the English physicist James Chadwick.
Olaf—An Atom Olaf—An Atom Olaf—An Atom is a 1913 American film directed by Anthony O'Sullivan and featuring Harry Carey. Broken by grief after his mother's death, Olaf becomes a wanderer. He is treated cruelly until he is given a meal by a woman at the homestead where she lives with her husband and baby. Olaf is able to return her kindness when he overhears a plot to rob the settlers of their home. He alerts the couple and delays the would-be thieves long enough for the husband to file a claim on his land. Olaf is injured by the claim jumpers but