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 Ant Atom" is available on the DVD "Saturday Morning Cartoons 1960s Vol. 1". The episode "Atom Ant Meets Karate Ant" is available on the DVD "Saturday Morning Cartoons 1960s Vol.2". The episode "The Big Gimmick" is available on the DVD "Best of Warner Bros. 25 Cartoon Collection Hanna-Barbera". On October 6, 2015, Warner Archive released "Atom Ant: The Complete Series" on DVD in region 1 as part of their Hanna–Barbera Classics Collection. This is a Manufacture-on-Demand (MOD) release, available exclusively through Warner's online store and Amazon.com. In 2016, "The Atom Ant Show" was made available for download via iTunes Store. Both