Background: Atomic physics and nuclear matter physics are often exclusively studied. However, atomic properties are a direct function of nuclear properties. Establishing a mathematical relationship between nuclear and atomic properties could serve the interest of nuclear and atomic engineers. Nuclear - and atomic-based instrumentation engineering and nuclear medicine (and perhaps atomic medicine) applications could be the benefits. Objectives: The research is undertaken to 1) link nuclear property, the mass-radius of the nucleon, and ionization energy of hydrogen via the derivation of appropriate equation and 2) determine the mass-radii of the nucleons and some leptons. Methods: Theoretical and computational methods. Results and Discussion: As applicable to the previous results in the literature, the larger the mass of the elementary particles, the longer the radii. For the particles investigated, the order of the radius is muon (m-)+)< neutron (n)< tauon (t-) corresponding to increasing mass, m-+< n-. The values of the mass radii were respectively » 0.1240, 1.1012, 1.1027, and 2.0855 fm. Conclusion: Nuclear properties such as the radius of any nucleon (ΓN) can be mathematically linked to atomic properties such as the ionization energy of hydrogen via equation which shows that ΓN is inversely proportional to the ionization energy of hydrogen and directly proportional to the rest-mass of the particle.