Eight is a magic number for protons and 20 for neutrons, so oxygen-28 was expected to be one of these doubly magic isotopes. Instead, its instability led scientists to conclude that the nuclear ...

Protons sit in the nuclei of all atoms, but they are not fundamental particles: They are made of three quarks held together by the strong nuclear force. The strength of this interaction is ...

As they studied atomic disintegration, they kept seeing that the atomic number (number of protons in the nucleus, equivalent to the positive charge of the atom) was less than the atomic mass ...