Final answer:
NaCl will have the highest melting point due to its ionic nature and strong intermolecular forces. NaF, NaBr, and NaI are covalent compounds with lower melting points. NaI will have the highest melting point among the covalent compounds due to the size of the iodine atom and the strength of dispersion forces.
Step-by-step explanation:
The compound with the highest melting point in this case would be NaCl. This is because NaCl is an ionic compound, formed by the electrostatic attraction between Na+ and Cl- ions. Ionic compounds generally have high melting points due to the strong forces of attraction between the ions. In NaCl, the positive sodium ion is attracted to the negative chloride ion, forming a crystal lattice structure with strong intermolecular forces.
On the other hand, NaF, NaBr, and NaI are all covalent compounds, formed by the sharing of electrons between atoms. Covalent compounds generally have lower melting points compared to ionic compounds because the intermolecular forces are weaker. The strength of the intermolecular forces in covalent compounds depends on factors such as the polarity of the bonds and the size of the atoms involved.
In this case, NaF would have the lowest melting point among the three covalent compounds because fluorine is the most electronegative element and it forms the most polar bond with sodium. NaBr would have a higher melting point compared to NaF due to the larger size of the bromine atom, which increases the strength of dispersion forces. NaI would have the highest melting point among the covalent compounds because iodine is the largest atom, resulting in the strongest dispersion forces.