Why is Carbon Special?
Carbon
• Tetravalency: Carbon has four valence electrons and forms four strong covalent bonds.
• Catenation: Stable C–C bonds let atoms link into long chains, rings or branches.
• Variable bonding: Carbon uses single, double and triple bonds for vast structural variety.
Together, these traits enable millions of carbon compounds.
Build a Covalent Bond
Octet Rule in Action
Atoms seek stability by completing an eight-electron outer shell, called the octet rule.
In covalent bonding, atoms share electrons; ionic bonding transfers them.
Drag each unpaired carbon electron onto a hydrogen to share a pair and form methane \( \mathrm{CH_4} \).
When carbon and all hydrogens show full shells, you have proven covalent bond formation by the octet rule.
Allotropes of Carbon
Diamond • Graphite • Fullerene
Diamond: 3-D sp³ lattice; hardest natural solid; electrical insulator.
Graphite: Stacked hexagonal sp² sheets; soft, slippery; good conductor.
Fullerene (C₆₀): Hollow soccer-ball cage; molecular solid; key to nanotechnology.
Classification of Hydrocarbons
Hydrocarbons
Hydrocarbons contain only carbon and hydrogen. They fall into: Saturated Alkanes with single \( \mathrm{C{-}C} \) bonds; Unsaturated Alkenes with at least one \( \mathrm{C{=}C} \); and Unsaturated Alkynes with at least one \( \mathrm{C{\equiv}C} \). Knowing the bond type lets you classify any hydrocarbon as an alkane, alkene, or alkyne.
Test Your Nomenclature Skills
What is the IUPAC name of CH₃-CH₂-CH₃?
Choose the correct option:
A) Methane B) Ethane C) Propane D) Butane
Hint: Three carbon atoms give root “prop-”, no substituents mean no prefix, and saturation adds the suffix “-ane”.
Functional Groups Add Variety
Functional Group
An atom or set of atoms—such as –OH, –COOH, or –Cl—that replaces hydrogen in a carbon chain and controls the molecule’s physical and chemical behaviour.
• Hydroxyl (–OH) → alcohols • Carboxyl (–COOH) → carboxylic acids • Halogen (–Cl) → chloroalkanes. Identifying these groups helps predict solubility, acidity, and reactivity.
Ethanol & Ethanoic Acid
Key Properties & Uses
• Ethanol \( \text{C}_2\text{H}_5\text{OH} \): colorless, volatile, mixes with water, excellent solvent, burns with blue flame – used in beverages, sanitizers, fuels.
• Ethanoic acid \( \text{CH}_3\text{COOH} \): pungent, sour, miscible, freezes at 16 °C, main acid in vinegar – acts as preservative, and in plastics, esters, dyes production.
After this slide you should be able to list the chief properties and everyday applications of both compounds.
Reactions of Ethanol
C₂H₅OH
1. Oxidation: \( \mathrm{C_2H_5OH} + [O] \xrightarrow{\mathrm{KMnO_4/H^+}} \mathrm{CH_3COOH} + \mathrm{H_2O} \)
2. Dehydration: \( \mathrm{C_2H_5OH} \xrightarrow[\ 443\,\text{K}]{\mathrm{conc.\ H_2SO_4}} \mathrm{CH_2=CH_2} + \mathrm{H_2O} \)
3. Sodium reaction: \( 2\mathrm{C_2H_5OH} + 2\mathrm{Na} \rightarrow 2\mathrm{C_2H_5ONa} + \mathrm{H_2}\uparrow \)
You should now be able to explain how ethanol undergoes oxidation, dehydration, and a sodium reaction.
How Soaps Clean — Micelles
Micelle
In water, soap molecules self-assemble into spherical micelles. Hydrophobic tails tuck inward around grease, while hydrophilic heads face water. Rinsing lifts the trapped dirt away. Detergent micelles act similarly and remain effective in hard water.
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