Introduction

Atoms combine with each other to achieve stable electronic configuration. One way atoms combine is by sharing electrons, which forms a covalent bond.

Covalent bonding generally occurs between non-metal atoms where neither atom easily loses electrons. Instead, they share electrons to complete their outer shell.

Covalent bonds are common in materials such as diamond, silicon, and many organic compounds.

Definition

Covalent bonding is the chemical bond formed when two atoms share one or more pairs of electrons to achieve stability.

Formation of Covalent Bond

Covalent bonds are formed when two atoms share their valence electrons.

Steps involved:

1. Each atom contributes one or more electrons.

2. The electrons are shared between the atoms.

3. Sharing allows both atoms to achieve a stable outer electron shell.

Example of Covalent Bond

Hydrogen molecule (H₂)

Each hydrogen atom has 1 electron.

Two hydrogen atoms share their electrons.

H • + • H → H : H

Thus, both atoms achieve a stable configuration.

Another example:

Oxygen molecule (O₂)

Each oxygen atom has 6 valence electrons.

They share two pairs of electrons, forming a double covalent bond.

Types of Covalent Bonds

Covalent bonds may be classified based on the number of shared electron pairs.

Single bond → one pair of electrons shared
Double bond → two pairs of electrons shared
Triple bond → three pairs of electrons shared

Example:

H₂ → single bond
O₂ → double bond
N₂ → triple bond

Characteristics of Covalent Compounds

Covalent materials usually have the following properties:

Low melting and boiling points
Poor electrical conductivity
Strong directional bonds
Often exist as gases, liquids, or soft solids

However, some covalent materials like diamond are extremely hard.

Covalent Bonding in Engineering Materials

Covalent bonding is found in important engineering materials such as:

Diamond
Silicon
Germanium

These materials are used in:

Cutting tools (diamond)
Semiconductor devices (silicon)

Covalent bonding gives these materials high hardness and strong atomic bonding.

Difference Between Ionic and Covalent Bond

Exam-Focused Points

Covalent bond is formed by sharing electrons.

It usually occurs between non-metal atoms.

Types of covalent bonds include single, double, and triple bonds.

Covalent materials generally show poor electrical conductivity.

Diamond is an example of strong covalent bonding.

Example Competitive Exam Questions

What is covalent bonding?
Answer — Bond formed by sharing of electrons between atoms.

Which atoms usually form covalent bonds?
Answer — Non-metal atoms.

How many electron pairs are shared in a double bond?
Answer — Two pairs.

Why are covalent compounds poor conductors of electricity?
Answer — Because they lack free electrons.

Give an example of a covalent material used in engineering.
Answer — Diamond or silicon.

Quick Revision

Covalent bonding occurs by sharing electrons.

Occurs mainly between non-metals.

Types of bonds:

Single bond
Double bond
Triple bond

Covalent materials usually have low conductivity and strong directional bonding.