medium difficulty6 min

Properties of Ionic vs Covalent Compounds

Ionic and covalent compounds differ in properties because ionic compounds have ions in a lattice, while covalent compounds usually have molecules formed by shared electrons.

In one line: Structure first, property next.

Practice This Concept

Understand it

Ionic compounds generally have high melting points due to strong electrostatic attraction between ions. They conduct electricity in molten or aqueous state because ions are mobile. Many covalent compounds have lower melting and boiling points and do not conduct electricity because they have neutral molecules without mobile ions.

Example

Sodium chloride has a high melting point and conducts in solution, while sugar is covalent and does not conduct electricity in solution in the same way.

Rule to remember

Property rule: structure controls property; ionic lattice gives strong attraction and mobile-ion conduction when molten or aqueous, while covalent molecules usually lack mobile ions.

See it worked out

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

Worked example

If a solid has high melting point and conducts only when dissolved in water, it is likely ionic because fixed ions become mobile in solution.

Method you can reuse

1Read the observation.
2Check melting point, conductivity state, and solubility clue.
3Link each property to structure.
4Conclude ionic or covalent with reason.

Visual tip

A comparison table can show structure, melting point, conductivity, and solubility for ionic and covalent compounds.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why do molten ionic compounds conduct electricity but most covalent liquids do not?

Think first, then show answer

Molten ionic compounds contain mobile ions that can carry charge. Most covalent liquids contain neutral molecules, so they do not have mobile ions to conduct electricity.

Common wrong answer

Saying a dry ionic solid conducts because it has ions is incomplete and usually wrong, because the ions are fixed and cannot carry charge.

Don't mix this up

Students often memorise one property and apply it to all compounds. The correct property depends on structure and the presence of mobile charged particles.

Exam tip

For comparison answers, write property plus reason: high melting point due to strong ion attraction, conductivity due to mobile ions, and poor conductivity of covalent compounds due to neutral molecules.

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

Asked as property comparison, identification of compound type from observations, or reason-based questions on conductivity and melting point.

1
Enough for 1 mark
Ionic and covalent compounds differ in properties because ionic compounds have ions in a lattice, while covalent compounds usually have molecules formed by shared electrons.
2
Add for 2 marks
Example: Sodium chloride has a high melting point and conducts in solution, while sugar is covalent and does not conduct electricity in solution in the same way.
3
Add for 3 marks
Ionic compounds generally have high melting points due to strong electrostatic attraction between ions.

MCQ Quiz

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