@hwlau My AQA GCSE book states:
> Metals contain lots of electrons that move freely between the positively charged metal ions.
This perfectly makes sense. However, it goes on to say:
> These electrons stop the **ions moving away from each other.**
This coincides with other knowledge from other books that:
> The free electrons slow down when they collide with the fixed positive ions and their bound electrons.
What does the book mean by "the ions moving away from each other"?
Many thanks