medium difficulty5 min

Covalent Bonding

Covalent bonding is the chemical bonding formed when atoms share one or more pairs of electrons.

In one line: Covalent means common sharing.

Understand it

Covalent bonds commonly form between non-metal atoms. Instead of transferring electrons completely, atoms share electron pairs so that each atom gets a more stable outer-shell arrangement.

Example

In a chlorine molecule, two chlorine atoms share one pair of electrons, so each chlorine atom completes its outer shell.

Rule to remember

Covalent bond: sharing of electron pair(s), usually between non-metal atoms.

See it worked out

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

Worked example

1Oxygen has six valence electrons and needs two more.
2Two oxygen atoms share two pairs of electrons to form O₂ with a double covalent bond.

Method you can reuse

1Count valence electrons.
2Find how many electrons each atom needs.
3Share the required number of electron pairs.
4Check that outer shells are complete for school-level examples.

Sketch it in your answer

Draw electron-dot diagrams with shared pair(s) between atoms, such as Cl-Cl or H-O-H.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why do two chlorine atoms form a Cl₂ molecule by sharing electrons?

Think first, then show answer

Each chlorine atom has seven valence electrons and needs one more for a stable outer shell. By sharing one pair of electrons, both chlorine atoms complete their outer shells.

Common wrong answer

Writing that electrons are fully transferred in Cl₂.

Why it loses marks: Both atoms are non-metals and share electrons.

Don't mix this up

Students sometimes call every bond with non-metals weak. Covalent bonds within molecules can be strong, but forces between small molecules are often weak.

Exam tip

For covalent bonding answers, mention sharing of electron pairs and show shared electrons clearly in dot diagrams.