Question

The nucleus ${}_n^{m}X$ emits $\alpha$ particle and 2$\beta$ particles. The resulting nucleus is:

• A. ${}_{n-2}^{m-4}Y$
• B. ${}_{n-4}^{m-6}Z$
• C. ${}_n^{m-6}Z$
• D. ${}_n^{m-4}X$

Answer 1

The correct option is D ${}_n^{m-4}X$

Emission of $\alpha$ particle decreses mass number by 4 and atomic number by 2.

Emission of $\beta$ particle increases atomic number by 2.

Hence, the resulting nucleus is ${}_n^{m-4}X$.