Carbon is known for its remarkable versatility, allowing it to form a vast array of compounds essential for life. This versatility is due to its unique bonding properties and the ability to form complex structures.

4.2.1 Tetravalency and Hybridization

Carbon's tetravalency allows it to form four covalent bonds with other atoms. This characteristic, coupled with hybridization, enables the creation of diverse molecular structures:

• sp³ Hybridization: In this type, carbon forms four equivalent single bonds, leading to tetrahedral geometry. An example is methane (CH₄).
• sp² Hybridization: Involves one s orbital and two p orbitals mixing to form three sp² hybrid orbitals, creating a trigonal planar structure as seen in ethene (C₂H₄).
• sp Hybridization: Here, two p orbitals and one s orbital mix, resulting in linear structures such as ethyne (C₂H₂).

4.2.2 Formation of Different Compounds

Carbon's ability to bond with various elements leads to the formation of different types of compounds:

• Hydrocarbons: Compounds made up solely of carbon and hydrogen. They can be classified as:
  • Saturated Hydrocarbons (Alkanes): Contain only single bonds (e.g., propane, C₃H₈).
  • Unsaturated Hydrocarbons: Contain double or triple bonds (e.g., ethylene, C₂H₄, and acetylene, C₂H₂).
• Functional Group Compounds: Carbon forms compounds with functional groups, altering their properties. Common functional groups include:
  • -OH (hydroxyl group) in alcohols
  • -COOH (carboxyl group) in carboxylic acids
  • -NH₂ (amino group) in amines

4.2.3 Isomerism

The versatility of carbon leads to isomerism, where compounds have the same molecular formula but different structures:

• Structural Isomers: Compounds that differ in the arrangement of atoms. For instance, butane (C₄H₁₀) can exist as n-butane and isobutane.
• Stereoisomers: Compounds that have the same structure but differ in the spatial arrangement of atoms. Examples include cis-trans isomers in alkenes.

4.2.4 Formation of Complex Structures

Carbon's ability to form long chains and rings contributes to its versatility:

• Long Chains: Carbon can link together to form long chains, resulting in polymers and other complex molecules.
• Ring Structures: Carbon atoms can bond to form cyclic compounds, such as cyclohexane (C₆H₁₂).

4.2.5 Role in Biological Molecules

Carbon is the backbone of essential biological molecules:

• Proteins: Composed of amino acids, which contain carbon, hydrogen, oxygen, and nitrogen. The sequence and structure of amino acids determine protein function.
• Carbohydrates: Made of carbon, hydrogen, and oxygen, they serve as energy sources and structural components in living organisms.
• Nucleic Acids: DNA and RNA, vital for genetic information storage and transfer, are composed of carbon-containing nucleotides.

4.2.6 Applications in Industry

The versatile nature of carbon has numerous applications across various industries:

• Plastics: Carbon compounds are the basis for synthetic materials used in everyday products.
• Fuels: Hydrocarbons serve as primary energy sources in the form of fossil fuels and biofuels.
• Pharmaceuticals: Many drugs contain carbon compounds, playing critical roles in health and medicine.