Question

An element has $[Ar]3d^1$ configuration in its $+2$ oxidation state. Its position in the periodic table is

• A. period-3, group-3
• B. period-3, group-7
• C. period-4, group-3
• D. period-3, group-9

Answer 1

Answer: (C)

Electronic configuration of the element in $+2$ oxidation state is [Ar] $3d^1$.

This electronic configuration is obtained after losing 2 electrons.

$\therefore$ Atomic number of the element

$=$ Atomic number of $Ar+1+2$

$=18+1+2$

$=21$

Thus, element is scandium. It is a d-block element.

The electronic configuration of

$Sc=[Ar]3d^{1}4s^2$

Here, $n=4$ therefore, it belongs to the $4\text{th}$ period.

Group $=$ Total number of valence shell electrons $=3$

So, the element belongs to period-$4$, group-$3$.