Both isotopes and radioactive isotopes are pretty much the same but radioactive isotopes are better because it can be used to make medicine.
Yes, radioactive isotopes are largely used for the treatment of cancer.
Some examples are deuterium and tritium which are radioactive isotopes of hydrogen.
Zirconium does have radioactive isotopes, but the main ones used in industry are not radioactive.
Not all isotopes are radioactive; the radioactive isotopes are unstable and emit radiations.
Yes
Yes
Sodium has no radioactive isotopes.
Radioactive isotopes are not stable.
All the uranium isotopes are radioactive.
All radioactive isotopes will disintegrate.
Radioactive isotopes are used in medicine (treatment or diagnostic), as tracers in hydrogeology, physiology, sources of energy, standards for radiation, sterilization, radioactive dating, etc.