Carbon and its Compounds

What is Carbon?

Carbon is a non-metal element with the symbol 'C' and atomic number 6. It is found in nature in various forms, including graphite, diamond, and coal. Carbon is the building block of all life forms, playing a crucial role in organic chemistry.

Due to its tetravalency, carbon can form stable covalent bonds with other elements, resulting in a vast number of compounds.

Allotropes of Carbon

• Diamond: A crystalline form of carbon with each carbon atom bonded to four other carbon atoms in a tetrahedral arrangement. It is the hardest known natural material.
• Graphite: A soft, black form of carbon in which each carbon atom is bonded to three others, forming layers that can slide over each other. Graphite is a good conductor of electricity.
• Graphene: A single layer of carbon atoms arranged in a two-dimensional honeycomb lattice, known for its extraordinary strength and conductivity.
• Fullerenes: Molecules made entirely of carbon, usually in the form of spheres or tubes (e.g., buckminsterfullerene or C₆₀).

Bonding in Carbon Compounds

Carbon forms covalent bonds by sharing electrons. It can form single, double, or triple bonds depending on the number of electrons shared.

• Single Bond (σ-bond): Occurs when two carbon atoms share one pair of electrons (e.g., in methane, CH₄).
• Double Bond (π-bond): Occurs when two carbon atoms share two pairs of electrons (e.g., in ethene, C₂H₄).
• Triple Bond: Occurs when two carbon atoms share three pairs of electrons (e.g., in ethyne, C₂H₂).

Types of Carbon Compounds

Carbon forms a wide variety of compounds that can be classified into the following types:

• Organic Compounds: Compounds containing carbon, typically bonded to hydrogen, oxygen, nitrogen, and other elements. These include hydrocarbons, alcohols, acids, and esters.
• Inorganic Compounds: Carbon compounds such as carbonates and oxides, which do not follow the typical organic chemistry rules.

Hydrocarbons

Hydrocarbons are compounds made of only carbon and hydrogen. They can be classified as:

• Alkanes: Saturated hydrocarbons with single bonds between carbon atoms (e.g., methane, CH₄).
• Alkenes: Unsaturated hydrocarbons with at least one double bond between carbon atoms (e.g., ethene, C₂H₄).
• Alkynes: Unsaturated hydrocarbons with at least one triple bond between carbon atoms (e.g., ethyne, C₂H₂).
• Aromatic Hydrocarbons: Hydrocarbons with a benzene ring structure (e.g., benzene, C₆H₆).

Functional Groups in Organic Compounds

Functional groups are specific atoms or groups of atoms within molecules that are responsible for the characteristic reactions of those molecules. Common functional groups include:

• -OH (Hydroxyl Group): Found in alcohols (e.g., ethanol, C₂H₅OH).
• -COOH (Carboxyl Group): Found in carboxylic acids (e.g., acetic acid, CH₃COOH).
• -CHO (Aldehyde Group): Found in aldehydes (e.g., formaldehyde, CH₂O).
• -NH₂ (Amino Group): Found in amines (e.g., methylamine, CH₃NH₂).

Previous Year Questions

• RRB JE 2017: Which of the following is an example of an aromatic hydrocarbon?
• Benzene (C₆H₆)
• SSC JE 2018: Which compound contains a carboxyl group?
• Acetic acid (CH₃COOH)
• HSSC 2020: What is the common name of methane (CH₄)?
• Natural Gas

Conclusion

Carbon and its compounds are the foundation of organic chemistry and life itself. From simple hydrocarbons to complex organic molecules, carbon’s ability to form diverse compounds is unparalleled. Understanding carbon's bonding and the types of compounds it forms is essential for grasping chemistry and its many applications in daily life, industry, and medicine.