Practice: The lattice energy for ionic crystals decreases as the charge of the ions _____ and the size of the ions _____.
a) Increases, increases
b) Increases, decreases
c) Decreases, increases
d) Decreases, decreases
Lattice Energy is the estimate for the strength of ionic bonds.
Lattice Energy
Concept #1: Lattice Energy
Lattice Formation Energy involves an exothermic process where energy is released when gaseous ions combine into ionic solid.
Example #1: The lattice formation of MgBr2 is the energy change for which one of the following processes?
Concept #2: Lattice Dissociation Energy
Lattice Dissociation Energy involves an endothermic process where energy is absorbed when ionic solid is broken up into gaseous ions.
Example #2: Which of the following reactions is associated with the lattice dissociation of Li2O?
Concept #3: Lattice Energy Formula
Example #3: Which compound possesses the strongest ionic bond: MgBr2 or KCl?
Concept #4: Physical Properties
Larger Lattice Energy causes ionic bonds to be stronger. This in turn causes higher boiling and melting points, but lower solubility.
Example #4: Choose the compound below that should have the highest melting point according to the ionic bonding model.
Practice: Which of the following compounds would you expect to have the highest boiling point?
a) MgCl2
b) SrO
c) SrCl2
d) CsI
e) LiBr
Practice: The solubilities of CaCrO4 and PbCrO4 in water at 25°C are approximately 0.111 g/L and 0.0905 g/L in H2O respectively. Based on this information, which compound do you think has the smaller lattice energy?
