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.
Battle of the Atom Battle of the Atom "Battle of the Atom" is a 10-part comic book crossover storyline published by Marvel Comics that debuted in September and October 2013 and ran through multiple X-Men books. The story involves the X-Men of the future traveling to present time in order to force the time-displaced X-Men to return to their rightful time, as their presence in the current timeline will result in disastrous consequences. "Battle of the Atom" was announced in April 2013. The story involves the X-Men of the future traveling to present time in order to force the All-New X-Men to return to