Yes, there are several elements that do not have a stable number of both neutrons and protons. These elements are known as radioactive or unstable elements. Radioactive elements have nuclei that are not in a state of equilibrium, and they undergo spontaneous changes, known as radioactive decay, in order to attain a more stable configuration.
The stability of atomic nuclei is determined by the balance between the strong nuclear force, which holds the nucleus together, and the electrostatic repulsion between protons, which tends to push the nucleus apart. Elements with atomic numbers higher than lead (element 82) tend to have unstable nuclei.
For example, elements such as uranium (atomic number 92), thorium (atomic number 90), and plutonium (atomic number 94) have unstable isotopes. These isotopes have an excess of neutrons or protons compared to the number needed for stability, and they undergo radioactive decay to achieve a more stable configuration. During radioactive decay, these isotopes release radiation in the form of alpha particles, beta particles, or gamma rays.
It's worth noting that even for elements with stable isotopes, there may be some unstable isotopes present. However, these isotopes are typically short-lived and undergo radioactive decay relatively quickly. Elements with no stable isotopes at all are generally referred to as purely radioactive elements.
In summary, there are elements that do not have a stable number of both neutrons and protons. These elements have unstable isotopes and undergo radioactive decay to achieve a more stable configuration.