Here's why:

* Compounds are formed when two or more elements chemically combine in a fixed ratio. For example, water (H₂O) is a compound because it's made of hydrogen and oxygen in a 2:1 ratio.

* Alloys are mixtures of metals (and sometimes non-metals) that are mixed together to achieve specific properties. The elements in an alloy retain their individual properties, but the alloy itself has unique properties.

Bronze is typically a mixture of copper and tin. The proportions of copper and tin can vary depending on the desired properties of the bronze. Since the elements in bronze retain their individual properties, and the ratio of copper to tin is not fixed, bronze is an alloy, not a compound.