Ionic Bonding And Lattice Energy

Question

Among the ionic compounds NaF, NaCl, NaBr, and NaI, which one has the highest lattice energy and why?

RankGuru · Accepted Answer

Lattice energy is the energy released when gaseous ions combine to form one mole of a crystalline ionic compound. According to Coulomb's law, lattice energy is directly proportional to the product of ionic charges and inversely proportional to the interionic distance (sum of ionic radii). Since all four compounds share the same cation Na^+ and have the same ionic charges, the lattice energy depends mainly on the size of the anion. Fluoride (F^-) is the smallest halide ion with a radius of about 133 pm, while chloride, bromide, and iodide are progressively larger (181, 196, and 220 pm respectively). Smaller interionic distance in NaF means stronger electrostatic attraction and therefore higher lattice energy. NaI has the lowest lattice energy because iodide is the largest anion, maximising the interionic distance and weakening the electrostatic force. NaCl and NaBr have intermediate values. This pattern follows the NCERT-discussed Born-Haber cycle trend and is consistent with the higher melting point of NaF compared to other sodium halides. Verification: lattice energy of NaF (~923 kJ/mol) > NaCl (~788 kJ/mol) > NaBr (~741 kJ/mol) > NaI (~700 kJ/mol), confirming the trend.

Ionic Bonding And Lattice Energy

Select the correct option:

🔒 Solution Hidden from View

More chemical bonding and molecular structure Practice Questions

The Born-Haber cycle for the formation of MgCl_2 from its elements involves five enthalpy terms; if ...

According to Fajan's rules, which one of the following ionic compounds will have the maximum covalen...

Among NF_3 and BF_3, NF_3 has a dipole moment while BF_3 has zero dipole moment; the correct explana...

The bond angle in NH_3 is 107.3 degrees while that in PH_3 is 93.6 degrees; the most accurate explan...

The magnetic character and bond order of NO molecule, which has 15 electrons, as predicted by Molecu...

In the carbonate ion CO_3^{2-}, each carbon-oxygen bond has a bond order of 1.33; this non-integer b...

In valence bond theory, the concept of orbital overlap explains bond formation; which one of the fol...

Intramolecular hydrogen bonding in ortho-nitrophenol causes its boiling point to be lower than that ...

Carbon in CO_2 is sp hybridised; how many sigma (\sigma) bonds and pi (\pi) bonds are present in one...

Benzene's bond length is uniform at 1.40 Å, intermediate between a C-C single bond and a C=C double ...

Among the molecules CCl_4, CHCl_3, CH_2Cl_2, and CH_3Cl, the order of increasing dipole moment (from...

The boiling point of HF is anomalously higher than HCl despite HF having a lower molar mass; this is...

About This Question

Solution