What prevents the metals such as magnesium, aluminium, zinc and lead from oxidation at ordinary temperature

Metals such as magnesium, aluminium, zinc, and lead are protected from oxidation at ordinary temperatures due to the formation of a thin layer of oxide on their surface. This layer is formed when the metal reacts with oxygen in the air.

Here are the steps explaining this process:

1. When these metals are exposed to air, they react with the oxygen to form metal oxides. This is a process known as oxidation.

2. This oxidation process forms a thin layer of metal oxide on the surface of the metal.

3. This thin layer of metal oxide is adherent and impermeable, meaning it sticks to the metal surface and doesn't allow anything to pass through it.

4. This layer acts as a protective barrier that prevents further oxidation of the metal underneath.

5. Therefore, even though these metals are reactive, this protective oxide layer prevents them from being oxidized at ordinary temperatures.

This is why metals like magnesium, aluminium, zinc, and lead do not appear to rust or corrode like iron does. The protective oxide layer prevents the metal from further contact with oxygen, thus preventing further oxidation.