The mass defect of nuclear reaction: <br> is — Nuclear Chemistry and Radioactivity Chemistry Question

💡 Solution & Explanation

If $\Delta m$ is defined as $\text{Mass of products} - \text{Mass of reactants}$, using nuclear masses $m_{nucl}$: $\Delta m = m_{nucl}(\text{B}) + m_e - m_{nucl}(\text{Be})$. Converting to atomic masses: $\Delta m = (M_B - 5m_e) + m_e - (M_{Be} - 4m_e) = M_B - M_{Be}$. Therefore, correct answer is A.