Question

Given below are two statements :one is labelled as Assertion $A $ and the other is labelled as Reason $R$
Assertion A : In $T \ell I _{3},$ isomorphous to $CsI _{3},$ the metal is present in $+1 $ oxidation state.
Reason R : $T \ell$ metal has fourteen $f$ electrons in the electronic configuration.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. $A$ is correct but $R$ is not correct
• B. Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.
• C. $A$ is not correct but $R$ is correct
• D. Both $A$ and $R$ are correct but $R$ is $NOT$ the correct explanation of $A$.

Answer 1

Answer: (D)

$T \ell I_{3} \Rightarrow\left(T \ell^{\oplus} \,\&\, I_{3}^{\ominus}\right) $
$C s I_{3} \Rightarrow\left(C s^{\oplus} ; \,\&\, I_{3}^{\ominus}\right)$
[Both have same crystalline structure is called isomorphous]
$T \ell_{(81)}^{\oplus}=\left[X e_{54}\right] 4 f^{14}, 5 d^{10}, 6 s^{2}$
(It is correct due to present $14 f$ electrons in $T \ell^{\oplus}$ ion)