Which of the following is a characteristic property of electrovalent compounds?

Which of the following is generally true about ionic compounds?

Electrovalent compounds do not have

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

Which of the following statements is correct for $CsBr_3$?

Explain the Lattice Enthalpy.