The Born-Haber cycle is a thermodynamic cycle that relates the energy changes involved in forming an ionic compound from its elements. It is primarily used to determine the lattice energy by applying Hess's Law.

Ionization energy is the energy required to remove an electron from a gaseous atom, a crucial step for forming a cation in the Born-Haber cycle. This distinguishes it from electron affinity and lattice energy which have other roles.

Electron affinity is defined as the energy change, usually released, when a neutral atom gains an electron to form an anion. It is essential for understanding the exothermic step in ionic compound formation.

Sublimation energy is the energy required to convert a metal from its solid phase to its gaseous atomic form, which is an endothermic step in the Born-Haber cycle. This prepares the metal atoms for subsequent ionization.

Lattice energy is defined as the energy released when gaseous ions arrange into a crystalline ionic solid with strong electrostatic interactions. It is a key component of the Born-Haber cycle that compensates for energy consumed in earlier steps.

The correct sequence in the Born-Haber cycle begins with the sublimation of the metal, followed by ionization, then the electron affinity of the non-metal, and finally lattice formation. This sequence outlines the necessary energy changes required to form an ionic compound.

An exothermic overall reaction indicates that the energy released during lattice formation exceeds the energy required for the endothermic steps such as sublimation and ionization. The lattice energy plays a key role in compensating for these energy inputs.

Hess's Law states that the total enthalpy change of a reaction is the sum of the enthalpy changes of its individual steps. In the Born-Haber cycle, this principle allows the addition of energies from each step to arrive at the overall reaction enthalpy.

Lattice enthalpy, often synonymous with lattice energy, refers to the energy released when gaseous ions combine to form an ionic solid. This energy release is essential for the stabilization of the ionic structure.

After accounting for the energy consumed in sublimation, ionization, and the energy change from electron affinity, the remaining energy needed to complete the reaction equals the lattice energy. This approach uses Hess's Law to balance the cycle.

A high ionization energy means that more energy is required to remove an electron from the metal, making that step endothermic. This extra energy requirement can make the overall formation of the ionic compound less favorable unless compensated by a very exothermic lattice formation.

Lattice energy is the energy released when gaseous ions form a crystalline lattice, making it an exothermic process. Other steps such as sublimation and ionization generally require energy input, rendering them endothermic.

For ionic compounds derived from diatomic molecules, the bond dissociation energy is the energy required to break the molecular bond into separate atoms before ionization occurs. This step must be included in the cycle for an accurate energy balance.

The Born-Haber cycle for sodium chloride includes sublimation of sodium, its ionization, and the electron affinity of chlorine followed by lattice formation. The dissociation of NaCl is not a step, because the compound is being formed rather than broken apart.

The Born-Haber cycle illustrates that no matter which pathway is taken, the sum of the enthalpy changes will be the same. This direct application of Hess's Law shows the conservation of energy in chemical reactions.

By adding the sublimation and ionization energies (150 + 500 = 650 kJ/mol) and including the electron affinity (-350 kJ/mol), the net energy input before lattice formation is 300 kJ/mol. Using Hess's Law, lattice energy is -650 - 300, which equals approximately -950 kJ/mol.

Lattice energy is largely influenced by the distance between ions and how efficiently they pack in the crystal lattice. Differences in ionic radii and crystal structure can cause significant variations in lattice energy even when other energy parameters are similar.

A high bond dissociation energy means that more energy is required to break the diatomic bond into individual atoms. This additional energy is an endothermic contribution that must be counterbalanced by a larger, more exothermic lattice energy for the overall process to be favorable.

Typically, electron affinity is negative, meaning energy is released when a neutral atom gains an electron. A positive electron affinity indicates that energy must be supplied to form the anion, making the process less favorable and less exothermic.

The degree of ionic character is closely related to the lattice energy, as higher lattice energies generally indicate stronger electrostatic interactions and greater ionic character. Comparing the lattice energy with other energy terms in the cycle provides insight into the ionic versus covalent nature of the compound.