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Covalent Bond

A covalent bond is a chemical bond formed when two atoms share one or more pairs of electrons.

In one line: Share electrons, do not transfer them, when carbon makes stable molecules.

Practice This Concept

Understand it

Carbon and many non-metals prefer sharing electrons instead of losing or gaining them completely.
By sharing, each atom gets a more stable outer shell.
In carbon compounds, this idea is central because carbon usually forms strong covalent bonds with hydrogen, oxygen, nitrogen, and other carbon atoms.
That is why organic chemistry is built mainly around covalent bonding.

Example

In methane, CH₄, carbon shares one electron each with four hydrogen atoms and forms four single covalent bonds.

Rule to remember

A covalent bond is a shared electron pair.

Carbon is tetravalent, so it can form four covalent bonds.

Single, double, and triple bonds mean one, two, or three shared pairs of electrons.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

In CH₄, carbon has four valence electrons and each hydrogen has one.

1Carbon shares one electron with each hydrogen, so four shared pairs are formed.
2This gives carbon a stable octet and each hydrogen a stable duplet.

Method you can reuse

1Count the valence electrons of the atoms.
2Check whether transfer is easy or difficult.
3Show sharing of electron pairs.
4Write the structure.
5Verify that outer shells become stable.

Sketch it in your answer

Draw overlapping shells or electron-dot structures to show shared electron pairs in methane, ethene, or other simple carbon compounds.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why does carbon usually form covalent bonds in its compounds?

Think first, then show answer

Carbon has four valence electrons, so losing or gaining four electrons is difficult. It becomes stable by sharing electrons with other atoms, which is why it usually forms covalent bonds.

Common wrong answer

Carbon donates four electrons.

Why it loses marks: Carbon does not easily lose four electrons in normal organic compounds.

Don't mix this up

Students often think carbon gives away four electrons like a metal. Carbon does not usually form ions in simple carbon compounds.

Exam tip

While answering exam questions, always mention electron sharing and outer-shell stability, not electron transfer.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

Questions usually ask why carbon forms covalent compounds, how methane is bonded, or to draw an electron-dot structure of a simple molecule.

1
Enough for 1 mark
A covalent bond is a chemical bond formed when two atoms share one or more pairs of electrons.
2
Add for 2 marks
Example: In methane, CH₄, carbon shares one electron each with four hydrogen atoms and forms four single covalent bonds.
3
Add for 3 marks
Carbon and many non-metals prefer sharing electrons instead of losing or gaining them completely.

MCQ Quiz

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