Some isotopes are radioactive, some are not.
Succesive radioactive disintegrations in a radioactive series.
When an isotope is unstable, it is said to be radioactive.
The radioactive isotope is disintegrated in time and emit radiations.
Another isotope is produced.
when an isotope is it does not undergo radioactive decay
That's called a daughter isotope, or a daughter product. (The original isotope that decayed is the parent isotope.)
Succesive radioactive disintegrations in a radioactive series.
its called Half-Time...
When an isotope is unstable, it is said to be radioactive.
This is a radioactive isotope.
The radioactive isotope is disintegrated in time and emit radiations.
The radioactive isotope is disintegrated in time and emit radiations.
Another isotope is produced.
when an isotope is it does not undergo radioactive decay
This is called the "half-life" of the isotope.
It isn't really an ELEMENT that is unstable, but an ISOTOPE. That means that in general, for the same element, some atoms will decay, and some will not - the difference being the number of neutrons in the nucleus.
It's called "half life".