There are a total of 15 actinides in the actinide series and each are chemical elements with metallic properties. All of the actinide elements are radioactive and upon radioactive decay they release energy.
Yes. All of the actinides are radioactive.
All the uranium isotopes are radioactive.
All radioactive isotopes will disintegrate.
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.
All the isotopes of uranium are radioactive and unstable.
All isotopes of francium are radioactive.
Not all isotopes are radioactive; the radioactive isotopes are unstable and emit radiations.
Usually not, but all elements have radioactive isotopes.
None - they are all radioactive.
All the isotopes of promethium are radioactive.
All uranium compounds are radioactive to some degree.
After disintegration all radioactive elements are transformed in other elements.