(N/A) $(i)$ Ionic compounds have high melting and boiling points because a considerable amount of energy is required to break the strong inter-ionic electrostatic forces of attraction.
$(ii)$ Ionic compounds are soluble in water because the polar water molecules interact with the ions,overcoming the lattice energy and causing them to dissociate.
$(iii)$ They are solids and somewhat hard because of the strong electrostatic force of attraction between the oppositely charged ions,which holds them in a rigid crystal lattice structure.
$(iv)$ Ionic compounds conduct electricity in the molten state because the heat overcomes the electrostatic forces,allowing the ions to become free to move and carry charge.
$(v)$ Metals have a tendency to lose electrons to attain a stable,completely filled valence shell configuration (noble gas configuration).