Question

Calculate the number of $\alpha$ and $\beta$ particles is the following change :

$U_{92}^{235}⟶{}_{82}^{207}Pb$

• A. $\alpha -4;\beta -3$
• B. $\alpha -2;\beta -3$
• C. $\alpha -5;\beta -3$
• D. $\alpha -7;\beta -4$

Answer 1

The correct option is D $\alpha -7;\beta -4$

As the mass reduced from 235 to 207, there must be 7 alpha particles liberation as the mass reduces by 28. There must also be 4 beta particles as the atomic number reduces only by 10 not by 14.

$U_{92}^{235}⟶{}_{82}^{207}Pb+7{[}_2^4\alpha ]+4{[}_{-1}^0\beta ]$.

Hence, option D is correct.