Final answer:
The ionic compounds can be ranked according to their increasing lattice energy and melting point as follows: NaI, NaBr, NaCl, NaF.
Step-by-step explanation:
The melting point and lattice energy of ionic compounds are influenced by the charges and sizes of the ions involved. Higher lattice energy corresponds to stronger forces holding the ions together, resulting in higher melting points. In this case, we are comparing the lattice energy and melting points of four ionic compounds: NaF, NaBr, NaCl, and NaI.
- NaI would have the least lattice energy and melting point since it has the largest and least charged ions among the four compounds. The iodide ion (I-) is larger and has a lower charge compared to the other halide ions.
- NaBr would have the next highest lattice energy and melting point. Although bromide ions (Br-) are larger than chloride ions, they have a higher charge, resulting in stronger attractions.
- NaCl would have a higher lattice energy and melting point compared to NaBr because chloride ions (Cl-) are smaller and have a higher charge than bromide ions.
- NaF would have the highest lattice energy and melting point due to the combination of a small fluoride ion (F-) with a high charge.