Question

How many $\alpha and\beta$ -particles are emitted when an atom of ${}_{90}T{h}^{232}$ undergoes disintegration to produce an atom of ${}_{82}T{h}^{208}$

• A. 5,3
• B. 6,4
• C. 7,5
• D. 8,6

Answer 1

The correct option is B 6,4

${}_{90}T{h}^{232}{\to }_{82}P{b}^{208}+x_{2}H{e}^4+y_{-1}{e}^o$
Remembering that the total atomic number as well as mass number must be equal to the two sides of the equation, we have
208 + 4x + 0y = 232
i.e., 4x = 24 …(i)
and 82 + 2x – y = 90
or 2x – y = 8
Solving Equation (i) and (ii), we get x = 6 and y = 4.