| Matter |
Constituent of all physical objects, elementary particles are quarks and leptons |
| Quarks |
Collectively form hadrons, possess intrinsic qualities of spin, charge, and mass |
| Leptons |
Subject to weak nuclear and electromagnetic interactions, exist as electrons which combine with other particles, also exist as nuetrinos |
| Hadrons |
Subject to strong nuclear forces, two categories known as baryons and mesons |
| Mesons |
A hadron composed of three quarks |
| Baryons |
A hadron composed of one quark and one antiquark, exist as protons and neutrons |
| Nuclei |
A composite of mesons and baryons |
| Atoms |
Made up of nuclei and leptons |