Atoms and molecules: build the models
Build ball-and-stick models of common substances, count their atoms, and sort them into single atoms, molecules of elements and molecules of compounds.
Core concept
Atoms join to form molecules; a molecule of an element has one kind of atom, and a molecule of a compound has two or more kinds
Topic: Atoms and molecules
An atom is the smallest particle: A tiny piece that matter is made of, far too small to see. All key words of an element. A few elements, the noble gases such as helium and neon, exist as single atoms. Most atoms join to others to form molecules. If all the atoms in a molecule are the same, it is a molecule of an element, such as oxygen: A gas in the air that living things need to breathe and that fire needs to burn. All key words (O₂). If it contains two or more kinds of atom, it is a molecule of a compound, such as water (H₂O). In a ball-and-stick model, each ball is an atom, its colour shows the element, and each stick is a bond.
What you will learn
- Build ball-and-stick models of simple molecules.
- Count the atoms in a molecule from its formula.
- Distinguish atoms, molecules of elements and molecules of compounds.
Before you start
- Know the symbols of common elements.
Materials
- Modelling balls (white hydrogen, red oxygen, black carbon, blue nitrogen, green chlorine, yellow helium, purple neon and argon) and sticks
Equipment
- Molecular model kit
Procedure
- Choose a card and build its model with balls and sticks.
- Count how many atoms and how many kinds of atom it has.
- Place each card in the right group.