why is a radioisotope able to substitute for an ordinary (nonradioisotope) atom of the same element in a molecule?

Thank you - I'll take a look at that.

A radioisotope is able to substitute for an ordinary atom of the same element in a molecule because its chemical properties are essentially the same as those of the nonradioactive isotope of that element.

When a radioisotope replaces a nonradioactive isotope in a molecule, it becomes part of the molecule and participates in chemical reactions in the same way as the nonradioactive isotope. This is because the chemical behavior of an atom is primarily determined by its electron configuration and the number of protons in its nucleus, both of which remain the same regardless of whether the isotope is radioactive or not.

While radioisotopes undergo radioactive decay and emit radiation due to an unstable nucleus, this does not significantly affect their ability to participate in chemical reactions. The radiation emitted by a radioisotope results from changes in the nucleus, such as the emission of alpha particles, beta particles, or gamma rays, but this does not generally alter the atom's chemical behavior.

Therefore, whether an atom is a regular isotope or a radioisotope, it will occupy the same position in the periodic table and exhibit similar chemical properties. This property allows radioisotopes to be used in various applications, including medicine, industry, and scientific research.