Find the odd material (element vs alloy): Choose the one that is not a pure chemical element.

Introduction / Context:
Materials can be split into chemical elements versus mixtures/alloys. Zinc, silver, and platinum are elements from the periodic table; bronze is an alloy (commonly copper + tin), so it is compositionally distinct.

Given Data / Assumptions:

• Zinc (Zn): element.
• Silver (Ag): element.
• Platinum (Pt): element.
• Bronze: alloy (mixture), not a single element.

Concept / Approach:
Check whether each name denotes a solitary atomic species (element) or a mixture. Alloys are engineered combinations with properties distinct from their constituents.

Step-by-Step Solution:

Verification / Alternative check:
Periodic table membership confirms the element status of Zn, Ag, Pt; “bronze” does not appear as an element symbol.

Why Other Options Are Wrong:
They are pure elements and belong to the same class.

Common Pitfalls:
Do not confuse “silver color” in alloys with the element silver; naming conventions differ.

Final Answer:
Bronze