Question

Which statement is true about $n/p$ ratio?
A. It increases by $\beta - emission$
B. It increases by $\alpha - emission$
C. It increases by $\lambda - emission$
D. None of the above

Answer 1

To know whether which statement is true about the $n/p$ ratio, we will go through the whole concept of $n/p$ ratio and the effect of various decay processes on $n/p$ ratio. Then we will also discuss more about the $n/p$ ratio.

Complete step by step solution:
$n/p$ ratio increases by $\alpha - emission$ .
Effect of various decay process on $n/p$ ratio:
$*$ increases by $\alpha - decay$ .
$*$ decreases by $\beta - decay$ .
$*$ no-change by $\lambda - decay$ .
The $n/p$ ratio of an atomic nucleus is the ratio of its number of the neutron to its number of protons. Radioactive decay generally proceeds so as to change the $n/p$ ratio to increase stability. If the $n/p$ ratio is greater than 1 (which is always true for radioactive nuclei), alpha decay increases, the $n/p$ ratio.
The stability of the nucleus depends upon the neutron to proton ratio $n/p$ . If the number of neutrons against the number of protons for nuclei of various elements is plotted, it has been observed that most of the stable (non-radioactive) nuclei lie in a belt shown by a shaded region in figure this is called stability belt or stability zone. The concept of $n/p$ ratio is related to stability of the nucleus as when the nucleus becomes bigger, the electrostatic repulsions between the protons get weaker.
Hence, the correct option is B. It increases by $\alpha - emission$ .

Note:
Nuclear Chemistry Nature and Characteristics of Radioactivity (1.) The atomic numbers of all natural radioactive elements are comparatively high $\left( { > 83} \right)$ . The nuclei of these elements contain a large number of neutrons $(n)$ and protons $(p)$ and the $n/p$ ratio becomes greater than 1.5.