Element Carbon

Carbon (C)

Carbon is atomic number 6, a non-metal, and the backbone of all living things.

Quick check: Which household material is almost pure carbon?

Answer: Graphite in a pencil lead.

Valency 4

Carbon

Electronic configuration: 2,4. Its outer shell holds 4 electrons and needs 4 more for a stable octet. Instead of losing or gaining 4, carbon shares all 4 with other atoms. Therefore it forms four covalent bonds and shows valency 4.

Catenation Power

Catenation

Carbon bonds to itself again and again, creating long chains, rings, and branched structures.

Octane \(C_8H_{18}\) in petrol is an eight-carbon chain. Name another catenated molecule.

Why So Many Compounds?

Let’s unpack the trio of superpowers:

1

Tetravalency

Carbon makes four covalent bonds, letting it connect with many atoms simultaneously.

2

Catenation

Carbon atoms join to themselves forming chains, rings, or branches, creating countless frameworks.

3

Small Atomic Size

A compact nucleus gives strong, stable bonds, so large molecules stay intact.

Saturated vs Unsaturated

Saturated

Only single C–C bonds present.
Carbon valency fully satisfied—no more atoms can add.
General formula \( \mathrm{C_nH_{2n+2}} \).
Example: propane \( \mathrm{C_3H_8} \).

Unsaturated

Contain at least one double (C=C) or triple (C≡C) bond.
Extra bonding capacity lets other atoms add.
Alkenes: \( \mathrm{C_nH_{2n}} \); Alkynes: \( \mathrm{C_nH_{2n-2}} \).
Examples: ethene \( \mathrm{C_2H_4} \), ethyne \( \mathrm{C_2H_2} \).

Key Similarities

Both are organic compounds with C–C skeletons.
Both burn in air to give \( \mathrm{CO_2} \) and \( \mathrm{H_2O} \).

Multiple Choice Question

Question

What is the valency of carbon?

1
2
2
3
3
4
4
5

Hint:

How many electrons must carbon share to complete its octet?

Classify the Compounds

Drag each formula into the correct category based on its bond type.

Draggable Items

CH₄
C₂H₆
C₂H₄
C₂H₂

Drop Zones

Saturated

Unsaturated

Tip:

Saturated compounds have only single bonds; unsaturated compounds contain at least one double or triple bond.

Key Takeaways

Atomic identity

Carbon is element 6; its valency 4 lets it bond with four atoms.

Catenation power

Carbon atoms join to themselves, building long, branched or ring chains.

Millions of compounds

Small size plus tetravalency creates an enormous variety of carbon compounds.

Saturated vs unsaturated

Single C–C bonds give saturated compounds; double/triple bonds make them unsaturated.