Carbon’s Valency 4

Valency of Carbon

Carbon’s electron shells are arranged 2,4. The outer shell holds 4 electrons and needs 4 more for an octet. By sharing these electrons, carbon shows a valency of 4.

Key Characteristics:

  • Electron configuration: 2 in first shell, 4 in second.
  • Second shell is the valence shell.
  • Needs 4 more electrons to satisfy the octet rule.
  • Gains stability by forming four covalent bonds.

Covalent Bond

Covalent Bond

Two atoms form a covalent bond when they share one or more pairs of electrons, allowing each to reach a stable outer shell.

Think: Why is sharing easier for carbon than gaining or losing four electrons?
Answer: Moving four electrons needs more energy, so carbon prefers to share them.

Building Methane (CH₄)

Trace how one carbon forms four single covalent bonds with hydrogen to create methane.

1

Show Carbon’s 4 Valence Electrons

Write C and dot four unpaired electrons around it.

2

Add Four Hydrogen Atoms

Place H atoms nearby, each showing one valence electron.

3

Form Electron Pairs

Pair each hydrogen electron with one of carbon’s electrons to share.

4

Draw Single Covalent Bonds

Replace each shared pair with a line, giving four C–H single bonds.

5

Check Octet & Duet

Carbon now has 8 electrons; each hydrogen has 2. Methane formation is complete.

Pro Tip:

A single covalent bond equals one shared electron pair between two atoms.

Ionic or Covalent?

Carbon needs
octet
Gain 4 e⁻ → C⁴⁻
High energy
Lose 4 e⁻ → C⁴⁺
Higher energy
Energy too costly?
Shares e⁻
Covalent bond

Multiple Choice Question

Question

Carbon must gain how many electrons to achieve the nearest noble-gas (octet) configuration?

1
Two electrons
2
Four electrons
3
Six electrons
4
Eight electrons

Hint:

Carbon already has 4 valence electrons; a full octet needs 8.

Match the Molecule

Drag each molecule into its bond-type bucket: Single, Double, or Triple.

Draggable Items

CH₄
O₂
N₂

Drop Zones

Single Bond

Double Bond

Triple Bond

Tip:

Count the shared-pair lines: one line = single, two = double, three = triple.

Key Takeaways

Recap the main ideas

Valency = 4

Carbon needs four more electrons, so it forms four bonds.

Covalent Sharing

Atoms share pairs of electrons instead of transferring them.

Single, Double, Triple

Carbon creates C–C or C–X bonds with one, two or three shared pairs.

Sharing Saves Energy

Sharing four electrons costs less energy than gaining or losing four.

Lesson Wrap-Up

Carbon is tetravalent; it has four valence electrons.

It shares these electrons to complete an octet.

Shared electron pairs form strong covalent bonds.

Covalent bonding lets carbon create chains, rings, and countless compounds.

Next Steps

Great job! Next, we will see how these covalent bonds build molecules like ethane and ethene.

Thank You!

We hope you found this lesson informative and engaging.