Materials

Everything that we see or touch today is made up of some kinds of substances known as Materials. From things of our daily use like saucepans to the rockets going out into space are all made of some materials present on our Earth. 

1.0Understanding Materials

Materials are those substances that make everything around us, natural as well as synthetic. Materials are made by many natural or human-made processes. They can be classified based on their material properties, types, and structure.

Examples of materials are metals, ceramics, polymers, and composites.

Material Types

Materials may be classified into the following categories: 

Material Types	Visual Aid
Metals: Examples of Materials: Iron, Copper, Aluminum, Gold, etc. Conductors of heat and electricity. Malleable (it may be hammered into thin sheets) and ductile (it may be drawn into wires). High melting points and strength.
Non-Metals: Examples of Materials: Carbon, Oxygen, Nitrogen, Sulfur, etc. Poor conductors of heat and electricity. Brittle in a solid state and often has low melting points.
Polymers: Examples of Materials: Polyethylene, Nylon, Polystyrene, and Rubber. Made of long chains of molecules. They can be synthetic (plastics) or natural (rubber, cellulose). Flexible and light.
Ceramics: Examples of Materials: Clay, Glass, Cement, and Porcelain. Inorganic, non-metallic materials. Hard, brittle, and often resistant to high temperatures.
Composites: Examples of Materials: Reinforced concrete, fibreglass, and carbon fibre composites. Composed of two or more materials whose properties are different from others in order to improve their performance.

2.0Material Properties

Materials possess a variety of physical, chemical, and mechanical properties that decide their susceptibility for different applications: 

Physical Properties of Different Materials 

• Density: Mass per unit volume of a material.
• Melting/Boiling Point: The temperature at which a material changes state.
• Appearance of Materials: Colour, texture, and gloss define the look of the material.
• Hardness of Materials: The resistance of a material to surface deformation like scratching or indentation.
• The malleability of Materials: The capability of a material to get hammered or rolled into a thin sheet without breaking.
• Ductility of Materials: The capacity of being drawn into very thin wires without breaking.
• Electric Conductivity: The capability of a material to conduct electricity.
• Magnetic Properties: Attraction to magnetic fields (ferromagnetic, paramagnetic, diamagnetic).

Chemical Properties of Different Materials

• Reactivity: A material's response to reacting with other materials (e.g., oxidation, corrosion).
• Acidity/Basicity: The capacity to donate or accept protons (pH level).
• Flammability: It is the ability of a material to catch fire and burn.
• Oxidation Resistance: Stainless steel is resistant to rust and corrosion.

Mechanical Properties

• Strength: The capacity to absorb applied forces without breaking.
• Elasticity: The capacity to return to its original shape after deformation.
• Toughness: the capacity to absorb energy and plastically deform without fracturing.

3.0Materials in Atomic Table

The periodic table of elements has a significant role in explaining the properties and behaviours of different materials. The table gives information about the atomic structure, bonding, and periodic trends that influence the material properties of various Metals, Non-metals, metalloids, lanthanides, actinides, and transitional metals. 

Periodic Trends in Material Properties

• Electronegativity and Bonding: The electronegativity of elements determines their mode of bonding, leading to differences in material hardness, electrical conductivity, or reactivity.
• Atomic Size: Atomic size decreases across a period. This leads to stronger metallic bonding in metals and more stable covalent bonding in non-metals.
• Ionization Energy: The amount of energy needed to remove an electron from an atom, which affects the reactivity and chemical behaviour of materials.

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