How does decreasing the distance between ions in a lattice affect lattice energy?

How does decreasing the distance between ions in a lattice affect lattice energy?

• A. No Effect
• B. Increases
• C. Decreases
• D. Depends on Temperature

Answer: (B)

Decreasing the distance between ions strengthens their electrostatic attraction because the energy of interaction between charges scales roughly as 1/r. Lattice energy reflects the energy released when ions come together in a solid (and the energy needed to separate them again). When ions are closer, the attraction is stronger, so more energy is released to form the lattice and more energy is required to break it apart. In short, bringing ions closer increases the magnitude of lattice energy. Temperature doesn’t set this intrinsic distance effect in the basic picture (though it can alter distances a bit via expansion).

Decreasing the distance between ions strengthens their electrostatic attraction because the energy of interaction between charges scales roughly as 1/r. Lattice energy reflects the energy released when ions come together in a solid (and the energy needed to separate them again). When ions are closer, the attraction is stronger, so more energy is released to form the lattice and more energy is required to break it apart. In short, bringing ions closer increases the magnitude of lattice energy. Temperature doesn’t set this intrinsic distance effect in the basic picture (though it can alter distances a bit via expansion).