What is the role of the thin layer of oxide on the surfaces of metals like magnesium, aluminium, zinc, and lead at ordinary temperatures?

The thin layer of oxide on the surfaces of metals like magnesium, aluminium, zinc, and lead at ordinary temperatures acts as a protective barrier. This oxide layer forms upon exposure to air and prevents further corrosion or oxidation of the underlying metal. The oxide layer serves as a physical and chemical barrier, inhibiting the metal’s reaction with oxygen and moisture in the environment. This protective coating enhances the metals’ resistance to corrosion, maintaining their integrity and preventing deterioration. Regular atmospheric exposure allows these metals to passivate and develop a stable oxide layer, ensuring their durability in various applications.