Aradioisotope forms a stable isotope after it undergoes radioactive decay. which is the best conclusion to draw from this statement? it undergoes alpha decay. it undergoes beta decay. it does not participate in a decay series. it does not have a long half-life.

Answer : The correct option is "It does not participate in a decay series."

Explanation :

We have been given that the radioactive element forms a stable isotope after undergoing a radioactive decay.

Here the element becomes stable after emitting any one of the radiations. It is not emitting a series of radiations

Decay series is a process in which an element undergoes a series of radioactive decays in a definite sequence. Each nucleus formed after the decay behaves as a parent nucleus which further undergoes a decay till a stable nucleus is formed.

Example : Decay series of U-238

This element undergoes 14 radioactive decays and finally becomes U-208.

All the remaining options are not correct because we cannot draw any conclusions about the type of decay ( alpha or beta) or the half life from the given information.

The only conclusion that can be drawn is - It does not participate in a decay series.