any radioactive isotope can fission - true or false?

Answer 1

Any atom can be split under the right conditions except perhaps Hydrogen - the isotope without the neutrons. What is ther to fission a proton? So the answer is yes. Can any radioactive isotope fission spontaneously by itself - no.

Answer 2

The first answer is correct but I will add one thing. Radioactive isotopes decay to form a more stabile isotope or in some cases, another element. As part of this process, a particle is emitted from the atom. It is usually either a proton, a neutron or sometimes both. In any event, any particles that are emitted during this process are radioactive.