Which of the following substances has the highest melting point?

The electronic configurations of four elements $A, B, C, D$ are given below. Which of these elements is most likely to form an electrovalent (ionic) bond?

Which of the following halides has the maximum melting point?

Which of the following is incorrect for ionic compounds?

If the enthalpy of sublimation of $Li$ is $155 \ kJ \ mol^{-1}$, enthalpy of dissociation of $F_2$ is $150 \ kJ \ mol^{-1}$, ionization enthalpy of $Li$ is $520 \ kJ \ mol^{-1}$, electron gain enthalpy of $F$ is $-313 \ kJ \ mol^{-1}$, and standard enthalpy of formation of $LiF$ is $-594 \ kJ \ mol^{-1}$, then the magnitude of the lattice enthalpy of $LiF$ is . . . . . . $kJ \ mol^{-1}$ (nearest integer).

The electronic configurations of four elements $L$,$P$,$Q$,and $R$ are given as: $L (1s^2, 2s^2 2p^4)$; $Q (1s^2, 2s^2 2p^6, 3s^2 3p^5)$; $P (1s^2, 2s^2 2p^6, 3s^1)$; $R (1s^2, 2s^2 2p^6, 3s^2)$. The formulas of the ionic compounds that can be formed between these elements are: