Yes, there is a limit to the number of protons and neutrons that can be combined to form an atom. This limit is determined by the stability of the nucleus, which is governed by the balance between the electromagnetic force (which tends to repel protons) and the strong nuclear force (which binds protons and neutrons together).
The most stable and commonly found atoms in nature have relatively small atomic numbers. Hydrogen, for example, has one proton, while helium has two protons. As we move up the periodic table, the number of protons and neutrons in the nucleus increases. However, as the number of protons increases, the electromagnetic repulsion between the protons becomes stronger, requiring more neutrons to provide additional binding energy to hold the nucleus together.
The limit to the number of protons and neutrons that can be combined to form an atom is reached when the repulsive forces between protons become too strong to be counteracted by the strong nuclear force. This limit is commonly referred to as the "island of stability." The exact number of protons and neutrons that can exist in the island of stability is not precisely known, as it depends on the specific nuclear properties and interactions. However, it is believed that elements with extremely high atomic numbers, such as those beyond the transuranium elements, would be highly unstable and undergo radioactive decay.
In summary, while there is a limit to the number of protons and neutrons that can be combined to form an atom, the specific limit and stability of such atoms are still areas of ongoing research and exploration in nuclear physics.