Chapter 4 · ICSE Class 6 Chemistry (Selina Concise)

Elements, Compounds, Symbols and Formulae

Learn the difference between elements and compounds, and how chemical symbols and formulae represent them.

🔤 Chapter 4

An element compared with a compound, using oxygen and water as examples Two separate oxygen atoms representing the element oxygen with symbol O, and two hydrogen atoms bonded to one oxygen atom representing the compound water with formula H2O O₂ Element H₂O Compound
4.1

Elements and Compounds

An element is a pure substance made of only one type of atom. A compound is formed when two or more elements chemically combine in fixed proportions.

1

Is oxygen an element or a compound?

An element, since it's made of only one type of atom

2

Is water (H₂O) an element or a compound?

A compound, since it's formed from hydrogen and oxygen combined chemically

4.2

Chemical Symbols and Formulae

Each element has a chemical symbol (like O for oxygen, H for hydrogen). A chemical formula shows how many atoms of each element are in a compound.

1

What is the chemical symbol for oxygen?

O

2

What does the formula H₂O tell us?

It contains 2 atoms of hydrogen and 1 atom of oxygen

Practice

Exercises

1. What is an element?

2. What is a compound?

3. What is the chemical symbol for hydrogen?

4. What is the chemical symbol for carbon?

5. What does the formula CO₂ tell us about its composition?

Next chapter — Pure Substances and Mixtures, Separation of Mixtures 🧫 →