Bonding In Carbon-The Covalent Bond

Key Notes:

Nature of Carbon Bonding:

• Carbon atoms form covalent bonds, which involve the sharing of electrons between atoms.
• Carbon has 4 valence electrons, needing 4 more to fill its outer shell (octet), making it tetravalent.

Covalent Bond:

• A covalent bond is formed when two atoms share one or more pairs of electrons.
• In carbon compounds, each shared pair forms a single covalent bond.
• Covalent bonds are generally strong and stable.

Types of Covalent Bonds in Carbon:

• Single Bond (C – C): Involves the sharing of one pair of electrons (e.g., Ethane, C₂H₆​).

• Double Bond (C = C): Involves the sharing of two pairs of electrons (e.g., Ethene, C₂H₄​).

• Triple Bond (C ≡ C): Involves the sharing of three pairs of electrons (e.g., Ethyne, C₂H₂​).

Properties of Covalent Compounds:

• Generally, they have low melting and boiling points due to weak intermolecular forces.

• They are typically poor conductors of electricity since they do not have free ions or electrons.

• Covalent compounds are often non-polar, making them insoluble in water but soluble in organic solvents.

Allotropes of Carbon:

• Carbon exhibits allotropy, where the same element exists in different forms.
• Major allotropes include:
• Diamond: Each carbon atom is tetrahedrally bonded to four other carbon atoms, forming a rigid, three-dimensional structure. It is the hardest natural substance.

• Graphite: Carbon atoms are bonded in layers with weak forces between layers, making it soft and slippery. It can conduct electricity due to free-moving electrons.

• Fullerenes: Molecules made of carbon atoms arranged in hollow spheres (e.g., Buckminsterfullerene, C₆₀).

Significance of Carbon’s Bonding:

• The ability of carbon to form long chains and complex structures is the basis of organic chemistry.

• Carbon’s covalent bonding allows it to form a wide range of compounds with different properties, leading to the diversity of organic molecules found in living organisms.

Saturated vs. Unsaturated Compounds:

• Saturated hydrocarbons contain only single bonds between carbon atoms (e.g., alkanes).

• Unsaturated hydrocarbons have one or more double or triple bonds (e.g., alkenes, alkynes).

Isomerism:

• Carbon compounds can exhibit isomerism, where compounds with the same molecular formula have different structures or arrangements of atoms, leading to variations in properties.

Examples

• Methane (CH₄): The simplest organic compound where carbon forms four single covalent bonds with hydrogen atoms.

• Ethene (C₂H₄): A compound with a double bond between two carbon atoms, making it an unsaturated hydrocarbon.