To calculate the lattice energy of magnesium oxide MgO , we will use the Born-Haber cycle. The Born-Haber cycle is a series of steps that represent the formation of an ionic compound from its constituent elements. The steps are as follows:1. Sublimation of magnesium Mg to form gaseous magnesium atoms Mg g 2. Ionization of gaseous magnesium atoms Mg g to form gaseous magnesium ions Mg g 3. Dissociation of oxygen molecules O to form gaseous oxygen atoms O g 4. Electron affinity of oxygen atoms O g to form gaseous oxide ions O g 5. Formation of magnesium oxide MgO from gaseous magnesium ions Mg g and gaseous oxide ions O g The lattice energy of MgO is the energy released in step 5. We can calculate this by summing the energies of steps 1-4 and then subtracting the enthalpy of formation of MgO.Step 1: Enthalpy of sublimation of Mg = 147 kJ/molStep 2: First ionization energy of Mg = 738 kJ/molStep 3: Enthalpy of dissociation of O = 498 kJ/mol Since we need only 1/2 O molecule for one MgO molecule, we divide this value by 2: 498 kJ/mol 2 = 249 kJ/mol Step 4: Electron affinity of O = -141 kJ/mol Since we need 2 electrons for one O ion, we multiply this value by 2: -141 kJ/mol 2 = -282 kJ/mol Now, we sum the energies of steps 1-4:Total energy = 147 kJ/mol + 738 kJ/mol + 249 kJ/mol - 282 kJ/mol = 852 kJ/molFinally, we subtract the enthalpy of formation of MgO from the total energy to find the lattice energy:Lattice energy = Total energy - Enthalpy of formation of MgOLattice energy = 852 kJ/mol - -601 kJ/mol = 852 kJ/mol + 601 kJ/mol = 1453 kJ/molThe lattice energy of magnesium oxide MgO is 1453 kJ/mol.