Alloys exhibit irregular atomic arrangements in a metallic lattice

Steps:

• Define alloy as a homogeneous mixture of two or more metals or a metal and non-metal.
• Recall that alloy structures show atoms randomly substituting or interstitially placed in a lattice, unlike ordered pure metals or compounds.
• Examine diagrams: identify irregular mixing in one option versus regular patterns in others.
• Select the diagram depicting random atomic distribution as the alloy structure.

Why A is correct:

• A illustrates a substitutional alloy where different metal atoms randomly occupy lattice sites, matching the definition of a solid solution alloy.

Why the others are wrong:

• B shows a regular, uniform lattice typical of a pure metal crystal.
• C depicts an ordered ionic compound with distinct cation-anion arrangement.
• D represents a molecular structure with discrete units, not metallic bonding.

Final answer: A