In the given reaction
`._z X^A rarr ._(z+1)Y^A rarr ._(z-1) K^(A - 4) rarr ._(z-1) K^(A - 4)`
Radioactive radiations are emitted in the sequence.

Options

A. `alpha, beta, gamma`
B. `beta,alpha, gamma`
C. ` gamma,beta,alpha`
D. `beta,gamma,alpha`

Answer

B

Explanation

`._(Z)X^(A)to._(Z+1)Y^(A)to._(Z-1)B^(**A-4)to._(Z-1)B^(A-4)`
In going form X to Y, mass number remains unaffected, charge number increases by 1. Therefore, `beta`-particle must have been emitted. In going form Y and `B^(**)`, mass number decreases by 4 and charge number decreases by 2. therefore, an an `alpha` particle must have been emitted. In going form `B^(**)` to B, both mass number and charge number remain unaffected. Therefore, `gamma`-ray photon must have been emitted. Choice (b) is correct.