To calculate the lattice energy of CaF, we can use the Born-Lande equation:Lattice Energy = N * A * 1 - 1/n * q * q / 4 * r Where:- N is the Avogadro's number 6.022 x 10 mol - A is the Madelung constant for CaF, A = 2.977 - n is the Born exponent for CaF, n 10 - q and q are the charges on the ions for Ca, q = +2; for F, q = -1 - is the vacuum permittivity 8.854 x 10 C / N m - r is the distance between the ions 2.40 , which is equal to 2.40 x 10 m Now, let's plug in the values and calculate the lattice energy:Lattice Energy = 6.022 x 10 * 2.977 * 1 - 1/10 * +2 * -1 / 4 * 8.854 x 10 * 2.40 x 10 Lattice Energy = 6.022 x 10 * 2.977 * 0.9 * -2 / 4 * 8.854 x 10 * 2.40 x 10 Lattice Energy -2631 kJ/molThe negative sign indicates that the lattice energy is released when the crystal lattice is formed. Therefore, the lattice energy of CaF is approximately 2631 kJ/mol.