Question

Assertion (A) Element with electronic configuration $[ Ar ] 4 s^{2} 3 d^{5}$ is a $d$ - block element.
Reason (R) The last electron enters the $d$-orbital.

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

Answer 1

Answer: (A)

Element with electronic configuration $=[ Ar ] 4 s^{2} 3 d^{5}$ (manganese) is a $d$-block element because last electron enters the $d$-orbital.
Thus, both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.