Which is the least reactive metal in the reactivity series?

A - Copper

B - Mercury

C - Silver

D - Gold

The least reactive metal in the reactivity series among the options you've provided is D - Gold. To understand why gold is considered the least reactive, let's delve into the reactivity series and the properties of these metals.

Understanding the Reactivity Series

The reactivity series is a list of metals arranged in order of their reactivity from highest to lowest. This series helps us predict how metals will react with other substances, particularly acids and water. The more reactive a metal is, the more readily it will lose electrons and form positive ions.

Characteristics of the Metals

• Copper: Copper is relatively unreactive compared to many other metals, but it can react with strong acids and is known to tarnish when exposed to air over time.
• Mercury: Mercury is a liquid at room temperature and has low reactivity. It does not react with water and is less reactive than many metals, but it can still form compounds with other elements.
• Silver: Silver is also a noble metal, meaning it is resistant to corrosion and oxidation. However, it can tarnish when exposed to sulfur compounds.
• Gold: Gold is the least reactive of these options. It does not tarnish or corrode easily, which is why it is often used in jewelry and electronics.

Why Gold is the Least Reactive

Gold's position as the least reactive metal can be attributed to its atomic structure. It has a full outer electron shell, which makes it stable and less likely to participate in chemical reactions. This stability is a key reason why gold is often found in its native state in nature, unlike more reactive metals that typically form compounds.

Real-World Implications

The low reactivity of gold has practical implications. For instance, in the field of electronics, gold is used for connectors and circuit boards because it does not oxidize and maintains conductivity over time. In jewelry, its resistance to tarnishing ensures that pieces retain their luster and beauty for many years.

Summary

In summary, among the options of copper, mercury, silver, and gold, gold stands out as the least reactive metal. Its unique properties not only make it valuable in various applications but also highlight the fascinating nature of metals and their behaviors in chemical reactions.