# Why does lattice enthalpy decrease with increasing ionic size?

Lattice enthalpy decreases as ions get larger, but I have found two explanations:

1. The charge density is greater in smaller ions, so greater attraction
2. The ions are themselves able to get closer together, so greater attraction

Do these two explanations relate in any way? What would be the best explanation?

$$F = k\frac{q_1q_2}{r^2},$$
where $$q$$ is the magnitude of the charge, $$r$$ is the distance, and $$k$$ is the Coulomb’s constant.
Mathematically speaking, as $$r$$ increases, the magnitude of $$F$$ becomes smaller. As far as the charge density, as it increases, the magnitude of $$F$$ increases.
Just as $$\ce{MgO}$$ is stronger then $$\ce{NaCl}$$ since $$\ce{Mg}$$ and $$\ce{O}$$ have smaller ionic radii and they both bare a $$2+$$ and $$2-$$ charge, respectively, making the lattice enthalpy greater.