The **nuclear ratio** of an atomic nucleus is equal to the ratio of the number of the atomic neutrons to the number of the atomic protons. This can also be referred to as the neutron-proton ratio or N/P ratio. Considering the stable nuclei, the higher their atomic number, the higher the amount of this **nuclear ratio**.

This is due to the fact that the forces of electrical repulsive between protons scale are stronger than the nuclear force attractions. Precisely, most pairs of protons that are present in large nuclei are not distanced from themselves enough, and the electrical repulsion dominates over those strong nuclei forces.

Therefore, in stable larger nuclei, the proton density will be lower than that of stable smaller nuclei, where which more pairs of protons have short-ranged attractions of nuclear force. Taking oxygen, for example, in relation to our **nuclear ratio** definition; the number of neutrons and protons of oxygen are both 8. Then the **nuclear ratio** would be 8/8, which is equal to 1.