The relative abundances of the stable isotopes of the elements are not entirely constant. for example, in some geologic samples (soils and rocks) the ratio of 87sr to 86sr is affected by the presence of a radioactive isotope of another element, which slowly undergoes β decay to produce more 87sr. what is this other isotope?

The other isotope is

Explanation:

Beta decay is defined as the decay process in which a neutron gets converted to a proton and an electron.

In this decay process, beta particle is emitted. The emitted particle carries a charge of -1 units and has a mass of 0 units. The released beta particle is also known as electron.

The general equation for the beta decay process follows:

The chemical equation for the beta decay of an isotope that produces Sr-87 isotope follows:

The isotope that undergoes beta decay to form Strontium-87 isotope is Rubidium-87

Hence, the other isotope is