Energetics

Activity 1 - The limitations of models

Subtopic 15.1 - Energy cycles

NOS statement 1.10 - Models tested against experiments or data from observations may prove inadequate

Time: 5 min.

Task​: Lattice enthalpy values calculated from Born-Haber cycles are based on the "ionic model" which treats ionic compounds as containing 100 % ionic bonding.

a. Compare and explain the values for lithium iodide and sodium iodide.

b. Compare the values for sodium iodide and silver iodide.

c. Given that the ionic radii for Na+ is 102 pm and Ag+ is 115 pm, what problems presents itself in the comparison made in b.?

​d. Can you suggest an explanation?