Match list-I with list-II:

Identify the incorrect match.

1. (b), (ii)
2. (c), (iii)
3. (d), (iv)
4. (a), (i)

Match the element in column I with that in column II.

For the second period elements, the correct increasing order of first ionisation enthalpy is:

1.  Li<Be<B<C<O<N<F<Ne

2.  Li<Be<B<C<N<O<F<Ne

3.  Li<B<Be<C<O<N<F<Ne

4.  Li<B<Be<C<N<O<F<Ne

Magnesium reacts with an element (X) to form an ionic compound. If the ground state electronic configuration of (X) is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^3$, the simplest formula for this compound is : 

1. ${\mathrm{Mg}}_2{\mathrm{X}}_3$

2. ${\mathrm{MgX}}_2$

3. ${\mathrm{Mg}}_2\mathrm{X}$

4. ${\mathrm{Mg}}_3{\mathrm{X}}_2$

The incorrect match among the following is -

1. B < C < N < O (increasing first ionisation enthalpy)

2. I < Br < F < Cl (increasing electron gain enthalpy)

3. Li < Na < K < Rb (increasing metallic radius)

4. Al³⁺ < Mg²⁺ < Na⁺ <F^- (increasing ionic size)

Which one of the following orders is correct for the bond dissociation enthalpy of halogen

molecules?

1. Cl₂>Br₂>F₂>I₂               

2. Br₂>I₂>F₂>Cl₂

3. F₂>Cl₂>Br₂>I₂               

4. I₂>Br₂>Cl₂>F₂

The correct sequence of increasing radii is -

1. Ar < K⁺ < Ca²⁺

2. Ca²⁺ < Ar < K⁺

3. Ca²⁺ < K⁺ < Ar

4. K⁺ < Ar < Ca²⁺

The formation of the oxide ion O^2-(g), from oxygen atom requires first an exothermic and

then an endothermic step as shown below,

$$\begin{gathered} \mathrm{O}\left(\mathrm{g}\right) + \mathrm{e}- \stackrel{ }{\to } {\mathrm{O}}^{-}\left(\mathrm{g}\right); {∆}_{\mathrm{f}}\mathrm{H}° = -141{\mathrm{kJmol}}^{-1} \\ {\mathrm{O}}^{-}\left(\mathrm{g}\right) +\hspace{0.17em}{\mathrm{e}}^{-} \stackrel{ }{\to }{\mathrm{O}}^{2-}\left(\mathrm{g}\right); {∆}_{\mathrm{f}}\mathrm{H}° = +780 \mathrm{kJ} {\mathrm{mol}}^{-1} \end{gathered}$$

Thus, process of formation of O^2- in gas phase is unfavourable even though O^2- is

isoelectronic with neon. It is due to the fact that

1. electron repulsion outweighs the stability gained by achieving noble gas configuration

2. O^- ion has comparatively smaller size than oxygen atom

3. Oxygen is more electronegative

4. addition of electron in oxygen result in large size of the ion