Question

The ground state electronic configurations of the elements, $U$, $V$, $W$, $X$, and $Y$ (these symbols do not have any chemical significance) are as follows.

$U:1s^{2}2s^{2}2p^3$
$V:1s^{2}2s^{2}2p^{6}3s^1$
$W:1s^{2}2s^{2}2p^{6}3s^{2}3p^4$
$X:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{5}4s^2$
$Y:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^6$

Determine which sequence of elements satisfy the following statements:
(i) Element forms a carbonate which is not decomposed by heating.
(ii) Element is most likely to form coloured ionic compounds.
(iii) Element has the largest atomic radius.
(iv) Element forms only acidic oxide.

• A. $VWYU$
• B. $VXXW$
• C. $VWYX$
• D. $VXWU$

Answer 1

The correct option is B $VXXW$

(i) Element V with electronic configuration $1s^{2}2s^{2}2p^{6}3s^1$ is an alkali metal. It forms a carbonate which is not decomposed by heating. The carbonates of alkali metals are stable to heat.
(ii) Element X with electronic configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{5}4s^2$ is a d block element (a transition element). It is most likely to form colored ionic compounds due to the d-d transition of unpaired electrons.
(iii) Element X has the largest atomic radius
(iv) Element W with electronic configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^4$ is a p block element and forms only acidic oxide.
Hence, the sequence of elements that satisfy the given statements is V X X W.