A radioactive isotope is an unstable atom which emit radiations as alpha, beta, gamma, neutrons, positrons etc.
Most of the natural occurring (isotopes of) elements are NOT radioactive.Though most of all the known isotopes are radioactive but most of them do NOT naturally occur.
Some oxygen isotopes are radioactive, but they do not occur naturally.
Not all isotopes are radioactive; the radioactive isotopes are unstable and emit radiations.
Both isotopes and radioactive isotopes are pretty much the same but radioactive isotopes are better because it can be used to make medicine.
Sodium has no radioactive isotopes.
Radioactive isotopes are not stable.
All the uranium isotopes are radioactive.
All radioactive isotopes will disintegrate.
All isotopes of francium are radioactive.
The daughter isotope is the result of the radioactive disintegration of the parent isotope. For example radium is a product of the uranium disintegration.The two isotopes have different chemical (different atomic numbers, etc.), physical and nuclear properties.
It sure can; basically, each element has radioactive isotopes. Check the Wikipedia article "isotopes of oxygen" for more details.
radioactive isotopes! :)