JEE Main 2024 — Chemical Bonding And Molecular Structure Question with Solution

To determine the order of increasing ionic character in the bonds of the given molecules, we should consider the concept of electronegativity, which is a measure of the tendency of an atom to attract a bonding pair of electrons. The larger the difference in electronegativity between two atoms, the more ionic the bond is. Covalent bonds, on the other hand, have smaller differences in electronegativity.

We can qualitatively assess the ionic character of the bonds in each molecule as follows :

- ${\mathrm{N}}_2$ : Both nitrogen atoms have the same electronegativity since it is a diatomic molecule of the same element, therefore the bond is purely covalent with no ionic character.

- $\mathrm{S}{\mathrm{O}}_2$ : Sulfur and oxygen have different electronegativities, with oxygen being more electronegative than sulfur, but not as drastically different as in ionic compounds. Therefore, the bond has some ionic character but is primarily covalent.

- $\mathrm{Cl}{\mathrm{F}}_3$ : Chlorine and fluorine have different electronegativities, with fluorine being more electronegative. However, the difference is not as large as between metals and nonmetals, so while this bond has ionic character, it is not as ionic as a bond between a metal and a nonmetal.

- ${\mathrm{K}}_2\mathrm{O}$ : Potassium is a metal with low electronegativity, and oxygen is a nonmetal with high electronegativity. Therefore, bonds between potassium and oxygen will have a high degree of ionic character.

- $\mathrm{LiF}$ : Lithium is a metal with low electronegativity, and fluorine is a nonmetal with very high electronegativity. The difference in electronegativity is very large, indicating a very high ionic character, even more so than in ${\mathrm{K}}_2\mathrm{O}$ because fluorine is more electronegative than oxygen.

Given these considerations, the correct order from least to most ionic character is as follows :

$${\mathrm{N}}_2<\mathrm{S}{\mathrm{O}}_2<\mathrm{Cl}{\mathrm{F}}_3<{\mathrm{K}}_2\mathrm{O}<\mathrm{LiF}$$

Therefore, the correct option is :

Option A : $${\mathrm{N}}_2<\mathrm{S}{\mathrm{O}}_2<\mathrm{Cl}{\mathrm{F}}_3<{\mathrm{K}}_2\mathrm{O}<\mathrm{LiF}$$