Comprehensive Exam Revision Notes: Carbon, Life Processes, and Environment

Carbon, atomic number $6$, with an electronic configuration of $(2, 4)$, has a tetravalency of $4$, allowing it to form covalent bonds by sharing electrons. Key examples include methane ($CH_4$) and carbon dioxide ($CO_2$). Covalent compounds generally have low melting and boiling points and poor electrical conductivity.

Allotropes:

• Diamond: Hardest natural substance with a rigid structure.

• Graphite: Layers with free electrons, good electrical conductor.

• Fullerenes: Molecules like Buckminsterfullerene ($C_{60}$).

Carbon's versatility includes catenation and bonding capabilities.

Hydrocarbons:

• Saturated (Alkanes): Single bonds, $C_nH_{2n+2}$.

• Unsaturated:

  • Alkenes: At least one double bond, $C_nH_{2n}$.

  • Alkynes: At least one triple bond, $C_nH_{2n-2}$.

Functional Groups guide chemical properties, with a Homologous Series showing compounds differing by $-CH_2$.

IUPAC Nomenclature: Based on carbon count and functional groups.

Reactions: Includes combustion, oxidation, addition, and substitution.

Ethanol ($C_2H_5OH$): Liquid alcohol, used in solvents.
Ethanoic Acid ($CH_3COOH$): Vinegar solution.

Soaps: Carboxylic acid salts that trap dirt; ineffective in hard water. Detergents: Effective in soft and hard water.

Overall, carbon compounds play vital roles in biology, industry, and the environment.