Out of the following,which compound will have electrovalent bonding?

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

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 compounds has the highest lattice enthalpy?

Which type of compounds show high melting and boiling points?

Which of the following is least ionic?