Which of the following metals form a protective layer of its oxide on reaction with atmospheric oxygen?

Aluminium (Al) develops a passive layer of oxide when it reacts with oxygen due to the high reactivity of aluminium with oxygen. When aluminium comes in contact with oxygen, it reacts with it to form a thin layer of aluminium oxide (Al₂O₃) on its surface. This oxide layer acts as a protective barrier that prevents further oxidation of the metal.

The oxide layer on aluminium is passive because it does not react further with oxygen or other substances that come into contact with the metal. The oxide layer is formed by the reaction of aluminum with oxygen to form aluminium oxide, which adheres strongly to the surface of the aluminium.

The passive oxide layer on aluminium is self-repairing, which means that if it is scratched or damaged, the exposed aluminium reacts with oxygen in the air to form a new oxide layer. This property of self-repairing makes aluminium a popular choice for various industrial and manufacturing applications where corrosion resistance is important.