The number of beta particles emitted by radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter nuclei is as

1. isobar of parent
2. isomer of parent
3. isotone of parent
4. isotope of parent

isotope of parent

Reason — Given, number of beta particles emitted by radioactive substance is twice the number of alpha particles emitted by it.

Hence,

After alpha decay : $_{Z}^{A}\text{X} \longrightarrow _{Z-2}^{A-4}\text{Y} + _{2}^{4}\text{He}$

After beta decay : $_{Z-2}^{A-4}\text{Y} \longrightarrow _{Z-1}^{A-4}\text{Z} \longrightarrow _{Z}^{A-4}\text{W}$

• The daughter nucleus after alpha decay has its mass number reduced by 4.

• There will be no change in the reduced mass number after beta decay.

• The obtained daughter nucleus has a different mass number = (A-4) and the same atomic number = Z as the parent nucleus. So, the resulting daughter nuclei is an isotope of the parent.