Physical Properties of Metals and Nonmetals in Reaction with Air

Introduction:
Metals and nonmetals have different physical properties, including their reactions with air. When exposed to air, metals and nonmetals can undergo various reactions that result in changes in their physical appearance and properties.

Physical Properties of Metals:
- Lustre: Metals generally have a shiny and reflective surface, known as lustre.
- Malleability: Metals can be easily hammered into thin sheets without breaking, making them malleable.
- Ductility: Metals can be drawn into thin wires without breaking, making them ductile.
- Conductivity: Metals are good conductors of heat and electricity.
- Hardness: Metals are generally hard, but their hardness varies depending on the specific metal.
- Melting and Boiling Points: Most metals have high melting and boiling points.

Reactions of Metals with Air:
- Oxidation: When metals react with oxygen in the air, they undergo oxidation, forming metal oxides.
- Tarnishing: Some metals, such as iron and copper, can form a layer of oxide or sulfide on their surface when exposed to air for extended periods. This process is known as tarnishing.
- Corrosion: Certain metals, like iron, can undergo corrosion when exposed to air and moisture. Corrosion leads to the formation of metal oxides or hydroxides, weakening the metal's structure.

Physical Properties of Nonmetals:
- Dull Appearance: Nonmetals generally have a dull and non-reflective surface.
- Brittleness: Nonmetals are usually brittle and break easily when subjected to pressure.
- Non-Conductivity: Nonmetals are poor conductors of heat and electricity.
- Low Melting and Boiling Points: Nonmetals generally have low melting and boiling points compared to metals.

Reactions of Nonmetals with Air:
- Combustion: Nonmetals like carbon and sulfur can undergo combustion reactions with air when heated, producing oxides and releasing energy.
- Chemical Stability: Most nonmetals are chemically stable and do not readily react with air or oxygen.

Conclusion:
In conclusion, metals and nonmetals have contrasting physical properties when it comes to their reactions with air. Metals tend to be lustrous, malleable, ductile, and good conductors of heat and electricity. They can undergo oxidation, tarnishing, and corrosion when exposed to air. On the other hand, nonmetals have a dull appearance, are brittle, poor conductors, and have low melting and boiling points. Nonmetals can undergo combustion reactions but are generally chemically stable when exposed to air. Understanding these physical properties is essential in identifying and categorizing different elements based on their reactivity with air.