The Invisible Building Blocks

Why it matters

Keep cutting a piece of carbon in half, again and again. Eventually you reach a single carbon atom — the smallest piece that is still carbon. All matter is built from atoms like this.

Predict first

What is the smallest particle of an element that still has its properties?

Every element is made of tiny atoms. An atom has a nucleus of protons (and neutrons) with electrons around it. The number of protons decides which element it is.

• An atom — correct
• A tiny drop
• A grain of powder

What you do

Zoom in! Arrange the stages of the journey from a charcoal lump in your hand all the way down to one single atom.

Check yourself

What decides which element an atom is?

The proton number (atomic number) is the element's identity.

An atom is…

Atoms are the tiny building blocks of every element, far too small to see.

Dalton called atoms 'indivisible' building blocks. What does that mean?

Keep dividing carbon and the atom is where the cutting stops — anything smaller is no longer carbon.

• the number of protons — correct
• the number of neutrons
• its colour
• the smallest particle of an element that keeps its properties — correct
• just visible under a hand lens
• a kind of molecule
• An atom cannot be cut into smaller pieces that are still the same element — correct
• Atoms are too small to be seen
• Atoms never move or change place