There are several fundamental limits that prevent adding protons and neutrons together indefinitely to create atoms:
Nuclear Stability: As protons and neutrons are added to an atomic nucleus, the electrostatic repulsion between positively charged protons increases. At the same time, the strong nuclear force, which binds protons and neutrons together, tries to counteract this repulsion. However, there is a limit to how many protons and neutrons can be packed into a nucleus while maintaining stability. Beyond this limit, the electrostatic repulsion overcomes the nuclear force, leading to an unstable and highly energetic nucleus.
Binding Energy: Adding more protons and neutrons to an atomic nucleus increases its mass. However, the increase in mass does not occur linearly with the addition of each particle. The binding energy per nucleon, which represents the energy required to remove a nucleon from the nucleus, tends to decrease as the nucleus becomes larger. Therefore, after a certain point, adding more protons and neutrons becomes energetically unfavorable, as the binding energy per nucleon decreases and the system becomes less stable.
Neutron-to-Proton Ratio: The stability of an atomic nucleus also depends on the neutron-to-proton ratio. In general, stable nuclei have a balanced ratio of neutrons to protons. As the number of protons increases, the presence of additional neutrons becomes crucial for maintaining stability. However, there is a limit to the number of neutrons that can be added while keeping the nucleus stable. Nuclei that have an excess or deficiency of neutrons relative to protons tend to undergo radioactive decay to achieve a more stable configuration.
Nuclear Forces: The strong nuclear force, responsible for binding protons and neutrons together in the nucleus, has a limited range. It becomes less effective over longer distances. As the nucleus grows larger, the force becomes less influential, making it difficult to bind additional protons and neutrons together.
These limitations govern the structure and stability of atomic nuclei and define the boundaries for the formation of different elements.