STD 12 -1. Solution and colligative properties — JEE STD 11 Science — Question

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

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 largest atomic radius
$(iv)$ Element forms only acidic oxide

Assertion $(A)$ : $\mathrm{NH}_3$ and $\mathrm{NF}_3$ molecule have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of $\mathrm{NH}_3$ is greater than that of $\mathrm{NF}_3$.

Reason $(R)$ : In $\mathrm{NH}_3$, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the $\mathrm{N}-\mathrm{H}$ bonds. $\mathrm{F}$ is the most electronegative element.

In the light of the above statements, choose the correct answer from the options given below: