Copper does not corrode easily because it has a high resistance to corrosion. This is due to a protective layer that forms on its surface called a patina. The patina is a thin layer of copper oxide and copper carbonate that develops over time when copper is exposed to air and moisture.

The formation of the patina begins with the oxidation of copper, where copper atoms react with oxygen in the air to form copper(I) oxide. This oxide layer then reacts with carbon dioxide and moisture in the air to form copper carbonate. The copper carbonate layer provides additional protection to the metal surface.

The patina acts as a barrier between the copper and the surrounding environment, preventing further corrosion. It is stable and adheres to the surface of the copper, making it difficult for corrosive substances to reach the underlying metal. The patina also gives copper its characteristic greenish color.

The protective properties of copper make it suitable for various applications where corrosion resistance is important. It is commonly used in plumbing systems, electrical wiring, roofing, and decorative items.

In contrast, iron, zinc, and magnesium are more prone to corrosion. Iron readily reacts with oxygen and moisture in the air to form iron oxide, commonly known as rust. Zinc can corrode when exposed to moisture and air, leading to the formation of zinc oxide. Magnesium can also corrode in the presence of moisture and oxygen, forming magnesium oxide.

While these metals can be protected from corrosion through various methods such as coating or galvanization, copper naturally possesses a higher resistance to corrosion, making it a preferred choice in many applications.