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.
Atom (comics) Atom (comics) The Atom is a name shared by several fictional comic book superheroes from the DC Comics universe. The original Golden Age Atom, Al Pratt, was created by writer Bill O'Connor and artist Ben Flinton and first appeared in All-American Publications' "All-American Comics" #19 (Oct. 1940). The second Atom was the Silver Age Atom, Ray Palmer, who first appeared in 1961. The third Atom, Adam Cray, was a minor character present in Suicide Squad stories. The fourth Atom, Ryan Choi, debuted in a new "Atom" series in August 2006. Another Atom from the 853rd Century first appeared as part