What explains why metals are ductile or malleable?

The property of metals being ductile or malleable is primarily attributed to the ability of the atoms in metals to slide over each other. In a metallic bond, metal atoms are arranged in a lattice structure, surrounded by a 'sea' of delocalized electrons that enable them to move while still maintaining their bonds. When force is applied, the layers of atoms can shift without breaking the metallic bond, allowing metals to be drawn into wires (ductility) or hammered into thin sheets (malleability).

This characteristic is fundamental to understanding the mechanical properties of metals and differentiates them from materials that are brittle, where atoms do not have the same ability to move relative to one another without breaking.