Question

Assertion :${}_{92}^{238}\text{U}$ on $\alpha$-decay gives ${}_{90}^{234}\text{Th}$. Reason: The parent element and its daughter element formed after $\alpha$-decay are isodiaphers.

• A. $S$ is correct but $E$ is wrong
• B. $S$ is wrong but $E$ is correct
• C. Both $S$ and $E$ are correct and $E$ is correct explanation of $S$
• D. Both $S$ and $E$ are correct but $E$ is not correct explanation of $S$

Answer 1

The correct option is D Both $S$ and $E$ are correct but $E$ is not correct explanation of $S$

${}_{92}^{238}\text{U}$ on decay gives ${}_{90}^{234}\text{Th}$
The parent element and its daughter element formed after -decay are isodiaphers. They are atoms having same value of (np).
Thus ${}_{92}^{238}\text{U}$ and ${}_{90}^{234}\text{Th}$ areisodiaphers.
${}_{92}^{238}\text{U}⟶{}_{90}^{234}\text{Th}{+}_2^4\text{He}$
For ${}_{92}^{238}\text{U}$
n=146
p=92
np=54
For ${}_{90}^{234}\text{Th}$
n= 144
p= 90
np= 54
Both S and E are correct but E is not correct explanation of S.