Element or Compound?
Compare properties to distinguish between elements and compounds.
What this lesson covers
Why it matters
Hydrogen is one kind of atom — an element. Water is hydrogen locked to oxygen — a compound. The same hydrogen is inside, yet water is a completely different substance.
Predict first
What makes water a compound rather than an element?
An element contains only one kind of atom. A compound contains two or more elements chemically bonded in a fixed ratio, with new properties of its own.
- It is two different elements chemically bonded together — correct
- It is a liquid
- It is colourless and clear
What you do
No substance names this time — sort each PROPERTY card: does it describe an element, or a compound?
Check yourself
Which of these is an element?
Iron is a single kind of atom; water and salt are compounds of bonded elements.
Iron sulphide (FeS) is a compound because…
Two elements bonded in a fixed ratio make a compound — not its colour or state.
- Iron (Fe) — correct
- Water (H₂O)
- Common salt (NaCl)
- iron and sulphur are chemically bonded inside it — correct
- it is black in colour
- it is a solid