Elements

The idea

Elements are pure substances that cannot be broken down into simpler substances; they are the building blocks of all matter.

Hydrogen and oxygen

Water splits into hydrogen and oxygen. But hydrogen and oxygen cannot be split into simpler substances.

What are such substances called?

• Elements
• Mixtures
• Alloys

Sort them

Tap the bin where each one belongs.

Building blocks

Elements are pure substances. They cannot be broken down into simpler substances. They are the building blocks of all matter.

Elements are pure substances that cannot be broken down into simpler substances. They are the building blocks of all matter.

Notes

Elements cannot be broken down into simpler substances.

Check yourself

An element …

Which of these is an element?

Elements are called the building blocks of …

Hydrogen and oxygen are …

• is always a mixture. An element is a pure substance.
• cannot be broken down into simpler substances — correct. Yes!
• can be split by electricity into two gases. That is what happens to water, which is not an element.
• Water. Water breaks into hydrogen and oxygen.
• Sugar. Sugar decomposes into carbon and water.
• Gold — correct. Yes!
• all matter — correct. Yes!
• only metals. Elements build all matter.
• only gases. Elements build all matter.
• mixtures. They are pure substances that cannot be broken down.
• elements — correct. Yes!
• alloys. Alloys are mixtures of metals.