In the nuclear decay given below
`._Z^A X rarr ._(Z-1).^A Y rarr ._(Z-1)^(A - 4) B^** rarr ._(Z-1)^(A-1) B`,
the particle emitted in the sequence are

Options

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

Answer

A

Explanation

(a) In a nuclear reaction conservation of charge number and mass number must hold good.
Alpha particles are positively charged particle with charge `+ 2e` and mass `4 m`. Emission of an `alpha-`particle reduces the mass of the radionuclide by `4` and its atomic number by `2`. `beta-`particles are negatively charged particles with rest mass as well as charge same as that of electrons, `gamma-`particles carry no charge and mass.
Radioactive transition will be as follows
`._Z^A X rarr ._(Z+1).^AY + beta_(-1)^0`
`._(Z+1).^AY rarr ._(Z-1)^(A-4) beta + alpha_2^4`
`._(Z-1)^(A-4) beta rarr ._(Z-1)^(A-4)beta + gamma_0^0`.