Question

A radioactive atom '$X$' emits a $\beta$-particle to produce an atom '$Y$' which then emits an $\alpha$-particle to given an atom '$Z$':
(1) The atomic number of '$X$' is less than that of '$Z$'
(2) The atomic number of '$Y$' is less than that of '$Z$'
(3) The mass number of '$X$' is same as that of '$Y$'

• A. 1, 2 and 3 are correct
• B. 1 and 2 are correct
• C. 2 and 3 are correct
• D. 3 is correct

Answer 1

The correct option is D 3 is correct

+Z has lesser atomic number and mass number than both X and Y.

+ due to ${\beta }_0^1$ emission X and Y have same mass number..

Therefore only option 3 is correct.