With the help of an example, explain how the neutron to proton ra… - Vidyadip

Question

With the help of an example, explain how the neutron to proton ratio changes during $\alpha-$decay of a nucleus.

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Answer

Let us like the example of $\alpha-$decay of $^{238}_{92}\text{U}.$ The decay scheme is
$^{238}_{92}\text{U}\rightarrow ^{234}_{90}\text{Th}+^4_2\alpha \text{ (or}^4_2\text{He})$
Neutron to proton ratio before $\alpha-$decay $=\frac{238-92}{92}=\frac{146}{92}=1.59$
Neutron to proton ratio after $\alpha-$decay $=\frac{238-90}{90}=\frac{144}{90}=1.60$
$\frac{146}{92}<\frac{144}{90}$
This shows that the neutron to proton ratio increases during $\alpha-$decay of a nucleus.

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