Which statement best defines an alloy?

• A. A metallic substance composed of two or more elements
• B. A compound formed from a metal and a nonmetal with ionic bonding
• C. A single-element metal with impurity atoms
• D. A mixture of metals with no fixed composition

Answer: (A)

An alloy is a metallic substance composed of two or more elements, with at least one metal, fused or mixed to create a material whose properties differ from its constituents. This definition captures why alloys are created: combining elements to tailor strength, hardness, melting point, or other traits. The other descriptions don’t fit because an ionic compound formed from a metal and a nonmetal relies on ionic bonds rather than metallic bonding, which isn’t what an alloy is. A single-element metal with impurity atoms isn’t an alloy since it isn’t a substance of multiple elements. And a mixture of metals with no fixed composition describes a loose blend rather than a defined material system; real alloys have specific compositions or ranges that yield consistent properties.