Arrange the bonds in order of increasing ionic character in the molecules: $LiF$,$K_{2}O$,$N_{2}$,$SO_{2}$ and $ClF_{3}$

Two elements $X$ and $Y$ have the following electron configurations:
$X = 1s^2, 2s^2 2p^6, 3s^2 3p^6, 4s^2$
$Y = 1s^2, 2s^2 2p^6, 3s^2 3p^5$
The compound formed by the combination of $X$ and $Y$ is:

Which of the following is the correct order of lattice energy for the given ionic compounds?

Which bond in a molecule of ethyl magnesium bromide is ionic in nature?

The Born-Haber cycle for $KCl$ is evaluated with the following data:
$\Delta_{f} H^{\ominus}$ for $KCl = -436.7 \ kJ \ mol^{-1}$
$\Delta_{sub} H^{\ominus}$ for $K = 89.2 \ kJ \ mol^{-1}$
$\Delta_{ionization} H^{\ominus}$ for $K = 419.0 \ kJ \ mol^{-1}$
$\Delta_{electron \ gain} H^{\ominus}$ for $Cl_{(g)} = -348.6 \ kJ \ mol^{-1}$
$\Delta_{bond} H^{\ominus}$ for $Cl_2 = 243.0 \ kJ \ mol^{-1}$
The magnitude of lattice enthalpy of $KCl$ in $kJ \ mol^{-1}$ is ..... . (Nearest integer)

Which type of bonding exists in $Li_2O$ and $CaF_2$ respectively?