Which of the following pairs of atomic numbers belongs to the same group in the periodic table?

In which of the following options does the order of arrangement not agree with the variation of property indicated against it?

Which of the following represents the correct order of ionization enthalpy?
$(i) Ba < Sr < Ca$
$(ii) S^{2-} < S < S^{2+}$
$(iii) C < O < N$
$(iv) Mg < Al < Si$

Fill in the blanks given below:
$(i)$ The most widely used scale for measuring electronegativity is ........ .
$(ii)$ The similarity observed in periodic properties is known as .............. .
$(iii)$ The elements located in the middle of the periodic table form .......... type of oxides.

Which of the following statements are correct for the classification of elements?
$I$. The properties of elements are periodic functions of their atomic numbers.
$II$. Non-metallic elements are less in number than the metallic elements.
$III$. The first ionisation energies of elements along a period do not vary in a regular manner.
$IV$. The ground state electronic configuration of $Pd (Z=46)$ is $[Kr] 4d^8 5s^2$.

Consider the following elements arranged in a periodic table segment as shown in the image (Row $1$: $A^{\prime}, B^{\prime}$; Row $2$: $C^{\prime}, D^{\prime}$ where $A^{\prime}$ is above $C^{\prime}$ and $B^{\prime}$ is above $D^{\prime}$). Which of the following is/are true about $A^{\prime}, B^{\prime}, C^{\prime}$ and $D^{\prime}$?
$A$. Order of atomic radii: $B^{\prime} < A^{\prime} < D^{\prime} < C^{\prime}$
$B$. Order of metallic character: $B^{\prime} < A^{\prime} < D^{\prime} < C^{\prime}$
$C$. Size of the element: $D^{\prime} < C^{\prime} < B^{\prime} < A^{\prime}$
$D$. Order of ionic radii: $B^{\prime+} < A^{\prime+} < D^{\prime+} < C^{\prime+}$
Choose the correct answer from the options given below: