The following compounds have been arranged in order of their increasing thermal stabilities. Identify the correct order
K₂ CO₃ ( I )     MgCO₃ ( II )   CaCO₃ ( III )   BeCO₃ ( IV )

For the molecules $\mathrm{LiF},{\mathrm{N}}_2,{ \mathrm{K}}_2\mathrm{O}$ and ${\mathrm{ClF}}_3,$ what is the correct arrangement of bonds in order of increasing ionic character?

Two elements $\mathrm{A}$ and $\mathrm{B}$ have electronegativities $1.2$ and $3.0$ respectively. The nature of bond between $\mathrm{A}$ and $\mathrm{B}$ would be

Assuming $\mathrm{AB}$ is an ionic compound and ${\mathrm{r}}_{\mathrm{c}}, {\mathrm{r}}_{\mathrm{a}}$ are the ionic radii of ${\mathrm{A}}^{+}$and ${\mathrm{B}}^{-}$respectively. The lattice energy of the compound $\mathrm{AB}$ is proportional to:

Match the following species with the correct number of electrons present in them:

The electronic configuration of element X is $2, 8, 8, 1$ and the electronic configuration of element Y is $2, 8, 7$. Then the type of bond formed between these two elements is

Give a reason for the following:

Ionic compounds have a high melting point.

What should be the correct order of lattice energy values of the following alkali halides?

$\mathrm{LiCl},\mathrm{KI},\mathrm{KCl}$and $\mathrm{NaCl}$