Question

For a radioactive nucleus that undergoes \(\beta ^{+}\) decay, which of the following CANNOT occur?

• A. Nuclei with lower atomic number than that of original nucleus is produced.
• B. The proton is converted to neutron
• C. Isobar of original nucleus is produced.
• D. Isotope of original nucleus is produced.

Hint:

In beta plus decay a proton turns into a neutron, so the atomic number falls by one while the mass number is unchanged.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
In \(\beta^{+}\) decay a proton changes into a neutron, a positron and a neutrino: \(p\rightarrow n+e^{+}+\nu\).

Step 2: Effect on the nucleus
The atomic number \(Z\) decreases by 1 and the mass number \(A\) stays the same. The daughter nucleus has a lower atomic number and is an isobar of the parent.

Step 3: Compare the options
Options (A), (B) and (C) all agree with this. An isotope needs the same \(Z\), which is not true here, so an isotope cannot be produced.

Final Answer:
An isotope of the original nucleus cannot be produced. \[ \boxed{\text{(D) }\text{Isotope of original nucleus is produced.}} \]