Model of an atom
Specification references:
• C1.1.4 Relative electrical charges of subatomic particles
• C1.1.5 Size and mass of atoms
• WS 1.2
Aims
In this activity you will have an opportunity to explore the “nuclear” model of the atom by building your own.
Learning outcomes
After completing this activity, you should be able to:
• describe the location of the protons, neutrons, and electrons in an atom
• use a model to develop scientific understanding.
Setting the scene
In science we use models to help us think about ideas and understand how they work better. The “atomic” model of the atom helps us to increase our knowledge of the structure of atoms and understand why atoms behave in the way they do.
Safety
Be careful not to get cut on the sharp edges of materials such as straws.
Equipment
• cotton wool balls
• coloured paper
• card
• wooden sticks
• pipe cleaners
• straws
• periodic table
Task
In this activity you will use the idea of the ‘atomic’ model of an atom to produce a model of a particular element. You will then evaluate your model and highlight its good points and its limitations.

Questions
1 Choose one of the atoms below. Circle the atom you have chosen. Note, the number next to each atom is its mass number.
4He, 7Li, 12C, 19F, 16O, 23Na
2 Work out the number of protons, neutrons, and electrons in your atom.

3 Describe where each type of particle is found within the atom.

4 Use the materials available to produce a model of your atom.
Sketch your model. Make sure it is fully labelled.
5 Explain which parts of your model are accurate when compared to a real atom.
6 Explain which parts of your model do not represent a real atom very well.
Student follow up
1 Add labels to complete the diagram below.

2 Complete the table to show the number of protons, neutrons and electrons in each of these atoms.
element proton neutron electron
4He 2
7Li 3
12C 6
19F 9
16O 8
23Na 12
31P 15
35Cl 18
39K 19
32S 16