Learning Objective

In this lesson we will learn about the main subatomic particles which make up atoms.

Learning Outcomes

By the end of this lesson you will be able to:

  • Describe the properties of protons, neutrons and electrons.
  • Describe the arrangement of protons, neutrons and electrons in an atom.
  • Describe the distribution of mass and charge within an atom.

 
structure of atoms lesson contents

(Image: nobeastsofierce, Adobe Stock)

Lesson Topics

1 | Atoms

2 | Protons

3 | Neutrons

4 | Electrons

5 | Nuclei

 


Lesson Summary

  • Atoms are composed of subatomic particles called protons, neutrons and electrons.
  • Protons have a mass of 1 atomic mass unit and a positive charge (+1).
  • The number of protons determines the type of atom.
  • Neutrons have a mass of 1 atomic mass unit and no charge.
  • Electrons have a mass of 1/1800 of an atomic mass unit and a negative charge (–1).
  • Protons and neutrons form a dense cluster at the centre of an atom, called a nucleus.
  • Electrons move around the nucleus, forming an electron cloud.

 
atom structure labelled protons electrons neutrons nucleus

 

Particle / Structure Location Charge Mass (atomic mass units)
Proton Nucleus +1 1
Neutron Nucleus 0 1
Electron Electron Cloud –1 1/1800
Nucleus Centre of atom positive
(amount depends on atom)
(depends on atom)
Electron Cloud Around the nucleus negative
(amount depends on atom)
(depends on atom, but negligible)
Atom 0 (depends on atom, approximately same as nucleus)

Summary of atomic structure

(Header image: geralt, Pixabay)

 


 
structure of atoms worksheet

Click image to preview the worksheet for this lesson.

 
 
year 9 chemistry pdf workbook

Click image to preview the Year 9 Chemistry Workbook (PDF version).

 
 
Year 9 Chemistry Print Workbook Australian Curriculum

Click image to preview the Year 9 Chemistry Workbook (print version).

 
 
year 9 chemistry lesson notes australian curriculum

Click image to preview the Year 9 Chemistry Lesson Notes.