They emit particles, electromagnetic radiation, or both.* Apex*
Not all isotopes are radioactive; the radioactive isotopes are unstable and emit radiations.
All the uranium isotopes are radioactive.
All radioactive isotopes will disintegrate.
All isotopes of francium are radioactive.
The fate of all radioactive and unstable isotopes is the disintegration until to stable isotopes are obtained.
Not all of the transition elements are radioactive. Many of them are, and some of them have common radioactive isotopes, but some of them have no naturally occurring radioactive isotopes. Please note that all elements have synthetic radioactive isotopes, at least.
No, Barium has both stable and radioactive isotopes. Out of its 25 known isotopes, only 6 of them are considered radioactive. The most stable isotope of Barium is Barium-138, which is not radioactive.
No, there are many stable isotopes.
All radioactive elements eventually decay to lead (Pb). There a numerous isotopes of lead and it is thought that all the lead(Pb) in the world is derived from decayed radioactive isotopes.
All the actinides isotopes are radioactive; and the majority are artificial isotopes.
All the isotopes of uranium are radioactive and unstable.
Usually not, but all elements have radioactive isotopes.