As we go from left to right in period $2$ of the periodic table,the gram atomic volume of the elements:

The electronic configurations of four elements are:
$I. [Xe] \, 6s^1$
$II. [Xe] \, 4f^{14} \, 5d^1 \, 6s^2$
$III. [Ar] \, 4s^2 \, 4p^5$
$IV. [Ar] \, 3d^7 \, 4s^2$
Select the incorrect statement about these elements.

Consider the following values of $IE$ $(eV)$ for elements $W$ and $X$:

Element	$IE_1$	$IE_2$	$IE_3$	$IE_4$
$W$	$10.5$	$15.5$	$24.9$	$79.8$
$X$	$8$	$14.8$	$78.9$	$105.8$

Other two elements $Y$ and $Z$ have outer electronic configuration $ns^2 np^4$ and $ns^2 np^5$ respectively. According to the given information,which of the following compound$(s)$ is/are not possible?
$(a) W_2Y_3, (b) X_2Y_3, (c) WZ_2, (d) XZ_2$

The incorrect order of properties for the following is:

The first element of a group differs in many ways from the other heavier members of the group due to:

Which of the following statements is not correct?