Answer:
Radioactive elements
Stable
Explanation:
Radioactive elements that have a longer half-life are more stable than those that a shorter half-life.
Half-life is the time taken for half of a radioactive element to decay by half of its original composition.
Now, if a substance have a long half-life, it is more stable and takes time to break down. For atoms with a short life, they are highly unstable and breaks down readily and easily.
