Here's why:

* Electrons: Thomson's famous cathode ray tube experiments led to the discovery of negatively charged particles, which he named electrons.

* Neutrons: The neutron was discovered by James Chadwick in 1932.

* Isotopes: While Thomson's work laid the groundwork for understanding isotopes (atoms of the same element with different numbers of neutrons), the concept was further developed by Frederick Soddy.

* Protons: The proton was discovered by Ernest Rutherford, who also established the nuclear model of the atom.