Size and mass of atoms (AQA GCSE Chemistry & Combined Science)

This lesson describes the size and mass of atoms and describes the relative mass and electrical charge of the subatomic particles. The PowerPoint and accompanying resources are part of the first lesson in a series of 3 that has been designed to cover specification points 1.1.4 - 1.1.6 of the AQA GCSE Chemistry & Combined Science specifications.

The lesson begins by introducing giga as a prefix of size and this leads into a task where the students have to order the other prefixes from largest to smallest. This introduces the nanometre and students will learn the size of the radius of an atom is 0.1nm. Time is taken to compare this size against that of a football and a human egg cell to try to put this atom radius into context. Moving forwards, the term “subatomic particles” is introduced and the students are challenged to recall the names of the three types along with their location within the atom from their lessons on the development of the atomic model earlier in topic 1. They are told that most of atom’s mass is in the nucleus and therefore can work out the protons and neutrons have much higher relative masses than electrons. They will also learn the relative electrical charges of the particles and are challenged to use this to state the overall charge of an atom and the nucleus.
There is a considerable amount of Maths written into this lesson including the use of standard form and conversion between units and step by step guides are used to support the students with this work