In ionic lattices, what happens to lattice energy when ions get closer together (distance decreases)?

In ionic lattices, what happens to lattice energy when ions get closer together (distance decreases)?

• A. Lattice Energy Is Independent of Distance
• B. Lattice Energy Increases with Increasing Distance
• C. Lattice Energy Decreases with Decreasing Distance
• D. Lattice Energy Increases as Ions Get Closer

Answer: (D)

The main idea here is how the electrostatic forces between ions set the strength of an ionic lattice and how that strength depends on how close the ions are. Lattice energy measures the energy released when gaseous ions come together to form the solid (or, equivalently, the energy required to separate the solid into gaseous ions). Because the attraction between opposite charges follows Coulomb’s law, getting ions closer increases the strength of their attraction, so more energy is released when the lattice forms. In other words, the smaller the distance between ions, the larger the magnitude of the lattice energy. If the ions were pulled farther apart, the attraction weakens and the lattice energy would be smaller. Therefore, lattice energy increases as ions get closer.

The main idea here is how the electrostatic forces between ions set the strength of an ionic lattice and how that strength depends on how close the ions are. Lattice energy measures the energy released when gaseous ions come together to form the solid (or, equivalently, the energy required to separate the solid into gaseous ions). Because the attraction between opposite charges follows Coulomb’s law, getting ions closer increases the strength of their attraction, so more energy is released when the lattice forms. In other words, the smaller the distance between ions, the larger the magnitude of the lattice energy. If the ions were pulled farther apart, the attraction weakens and the lattice energy would be smaller. Therefore, lattice energy increases as ions get closer.