The third fundamental particle is the neutron, discovered in 1932 by James Chadwick (1891-1974) by bombarding a sheet of beryllium with alpha particles, he observed the emission by the metal of very high energy radiation, similar to gamma rays. Later studies showed that said radiation was made up of neutral particles (they do not respond to electric fields) with a mass slightly greater than that of protons.

The discovery of the neutron allowed us to understand the reason why the helium atom has a mass 4 times greater than that of hydrogen, containing only two protons. The explanation lies in the existence of 2 neutrons in its nucleus.

We use cookies

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.