A radioactive nucleus with `Z` protons and `N` neutrons emits an `alpha-`particle, `2 beta-`particle and `2 gamma` rays. The number of protons and neutrons in the nucleus left after the decay respectively, are

Options

A. `Z - 3,N - 1`
B. `Z - 2, N - 2`
C. `Z - 1, N - 3`
D. `Z,N - 4`

Answer

D

Explanation

(d) With emission of an `alpha` particle `(._2He^4)` mass number decreases by `4` unit and atomic number decrease by `2` units and with emission of `2 beta^-1` particle atomic number increases by `2` units. So `Z` will remain same and `N` become `N-4`.