Carbon and Its Compounds

Notes

1. Carbon Symbol: C Atomic Number: 6 Electronic Configuration: 2, 4 Valency: 4 (Tetravalent)

Carbon is an important element because it forms a very large number of compounds. All living organisms contain carbon.

2. Why Does Carbon Form So Many Compounds?

Carbon forms millions of compounds due to two unique properties.

(A) Catenation

Definition: The ability of carbon atoms to bond with other carbon atoms and form long chains, branched chains, and rings.

Examples:

C–C C–C–C Ring structures

Reason: Carbon-carbon bonds are very strong and stable.

(B) Tetravalency

Carbon has four valence electrons and needs four more electrons to complete its octet.

Instead of gaining or losing four electrons, carbon shares electrons with other atoms.

Hence, carbon forms four covalent bonds.

Examples:

CH₄ (Methane) C₂H₆ (Ethane) 3. Covalent Bond Definition

A covalent bond is formed by the sharing of electrons between two atoms.

Example

Hydrogen Molecule (H₂)

Each hydrogen atom shares one electron with another hydrogen atom to complete its duplet.

Methane (CH₄)

Carbon shares one electron with each of the four hydrogen atoms to complete its octet.

4. Properties of Covalent Compounds Physical Properties Usually gases or liquids. Some are soft solids. Have low melting points. Have low boiling points. Electrical Conductivity Do not conduct electricity. They do not produce ions in solution. Solubility Generally insoluble in water. Soluble in organic solvents like benzene and ether.
5. Saturated and Unsaturated Carbon Compounds Saturated Compounds (Alkanes)

Contain only single covalent bonds (C–C).

General Formula: CₙH₂ₙ₊₂

Examples:

Compound Formula Methane CH₄ Ethane C₂H₆ Propane C₃H₈ Butane C₄H₁₀ Unsaturated Compounds

Contain one or more double or triple bonds.

(A) Alkenes

Contain at least one double bond (C=C).

General Formula: CₙH₂ₙ

Examples:

Compound Formula Ethene C₂H₄ Propene C₃H₆ (B) Alkynes

Contain at least one triple bond (C≡C).

General Formula: CₙH₂ₙ₋₂

Examples:

Compound Formula Ethyne C₂H₂ Propyne C₃H₄ 6. Hydrocarbons

Hydrocarbons are compounds made up of only carbon and hydrogen atoms.