Concept:The reactivity of a metal is determined by its tendency to lose electrons (oxidize). Metals with high positive reduction potentials prefer to gain electrons rather than lose them, making them chemically stable or "noble."
Solution:- In the electrochemical series, elements placed below Hydrogen have positive standard reduction potentials (\( E^\circ_{red} > 0 \)).
- Coinage metals (Copper, Silver, Gold) all lie below Hydrogen in the series.
- A positive reduction potential indicates that they are poor reducing agents and very resistant to oxidation (corrosion), which is why they are ideal for making coins and jewelry.
Why other options are incorrect:Alkali and alkaline earth metals (like Na and Mg) have negative reduction potentials (and thus highly positive oxidation potentials), making them extremely reactive. Coinage metals are the opposite.
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