In Chapter $4,$ we learned that the atomic and ionic arrangements in materials are never perfect. We also saw that most engineered materials are not pure elements; they are alloys or blends of different elements or compounds. Different types of atoms or ions typically "diffuse", or move within the material, so the differences in their concentration are minimized. Diffusion refers to an observable net flux of atoms or other species. Diffusion depends upon the initial concentration gradient and temperature. Just as water flows from a mountain towards the sea to minimize its gravitational potential energy, atoms and ions have.a$.$ tendency to move in a predictable fashion so

as$.$to eliminate concentration differences and produce homogeneous, uniform compositions that make the material thermodynamically more stable.

$2$

Are the atomic and ionic arrangements in materials never perfect as we have learned before? How could this be possible? Please explain considering Arrhenius's equations and the $3$rd law of thermodynamics.