Final answer:
Ionic compounds have high melting points due to strong ionic bonds, and they can conduct electricity in a molten state or when dissolved in solution.
Step-by-step explanation:
Ionic compounds have high melting points because they are held together by strong ionic bonds in a 3D array of crystal lattices. The melting point of an ionic compound is higher than that of a molecular compound because the energy required to break the ionic bonds is much greater than the energy required to disrupt the intermolecular forces between molecules. For example, sodium chloride (NaCl) melts at 801 °C, while water (a molecular compound) melts at 0 °C.
Ionic compounds can conduct electricity when in a liquid state (molten) or in solution form, but not in solid form. This is because in the solid state, the ions in the ionic compound are held in a rigid structure and are unable to move freely. However, when molten or dissolved in solution, the ions are able to move freely and carry an electric charge, allowing the compound to conduct electricity.