Question

An element with atomic number 84 and mass number 218 loses one a-particle and two $\beta -$ particles in three successive stages. The resulting element will have

• A. at. no. 84 and mass no. 214
• B. at no. 82 and mass no. 214
• C. at. no. 84 and mass no. 218
• D. at. no. 82 and mass no. 218

Answer 1

Answer: (A)

Let element is 'A'. ${}_{84}{A}^{218}{\stackrel{\alpha -particle}{\to }}_{82}{B}^{214}{\stackrel{-\beta }{\to }}_{83}{C}^{214}$ ${\stackrel{-\beta }{\to }}_{84}{D}^{214}$ Hence, the resulting element will have at. no. 84 and mass no. 214.