Lattice is best described as:

• A. The three-dimensional array of atoms in a metal with a regular, repeating configuration in all directions.
• B. The ability of a metal to deform plastically under compressive load.
• C. The measure of the acidity or alkalinity of a solution.
• D. Internal voids in a material.

Answer: (A)

The main idea here is a crystal’s regular, repeating arrangement in space. In metals, atoms sit at specific points that form a three-dimensional, periodic pattern, creating a lattice that acts as the scaffolding for the crystal. This lattice is the abstract, infinite array of points that repeats in all directions, and the actual atoms (the basis) attach to those points to make up the material.

The best description matches a three-dimensional array of atoms in a metal with a regular repeating configuration in all directions, which captures the essence of a metal lattice and why crystals have their orderly structure and symmetry. The other options describe properties or features that are not about the spatial arrangement of atoms: ductility concerns how a material deforms under load, pH measures acidity/alkalinity, and internal voids describe porosity, not the organized lattice pattern.