Which set consists exclusively of coinage metals ?
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Answer: B. Cu Ag Au
Explanation
Copper, silver, and gold share similar chemical and physical properties within group eleven of the table. Human societies have utilized these three lustrous metals for minting currency throughout recorded history. Their resistance to corrosion and attractive appearance made them ideal choices for traditional metal coinage. Coinage metals are transition elements located in group eleven of the modern periodic table of elements. These elements occur naturally in the Earth's crust in elemental form or as stable mineral ores. They possess filled d-subshells that contribute to their unique noble character and high electrical conductivity.
Central banks historically backed national paper currencies with physical reserves of gold and silver. Modern circulation coins often use alloys containing copper to reduce material costs while retaining durability. Jewelers value coinage metals for their malleability, ductility, and resistance to tarnish over time. Mercury is a toxic liquid metal at room temperature, making it completely unsuitable for minting currency. Iron is a reactive structural metal prone to rapid rusting, disqualifying it as a traditional coinage metal. Mixing mercury or iron into a group alters the elemental set, invalidating options containing those metals.
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