Yes, there is a limit to the number of protons that can be added to an atom before it becomes unstable. This limit is determined by the balance between the electromagnetic forces that hold the nucleus together and the repulsive forces between protons.
The stability of an atom depends on the ratio of protons to neutrons in its nucleus. Atoms with a small number of protons, such as hydrogen or helium, tend to have roughly equal numbers of protons and neutrons. As the number of protons increases, more neutrons are needed to provide additional nuclear binding and counteract the increasing repulsion between protons.
However, there is a limit to this process. As the number of protons increases, the repulsive forces between protons become stronger, requiring an increasing number of neutrons to maintain stability. Eventually, this delicate balance breaks down, and the atom becomes unstable.
The specific limit depends on the element and is related to the concept of nuclear stability and the nuclear binding energy. Generally, atoms with very large atomic numbers (proton counts) tend to be highly unstable. These atoms often undergo radioactive decay, where they spontaneously release particles or energy in an attempt to reach a more stable state.
The precise value at which an atom becomes unstable varies depending on the specific nuclear properties and interactions. However, a commonly cited limit is the element with 84 protons, polonium. Elements beyond polonium in the periodic table typically exhibit increasing instability and radioactive behavior.
It's important to note that the stability of an atom also depends on factors beyond just the number of protons. The arrangement of neutrons, the presence of specific isotopes, and the overall nuclear structure all contribute to an atom's stability or instability.