BBC KS3 Bitesize
Written for schools but a useful basic guide, with animations, for anyone

BBC GCSE Bitesize
Written for GCSE courses, but useful for anyone wishing to learn more. For a change from reading, try the audio links too

The Periodic Table of Videos
Short videos on each element in the periodic table. An easy way to learn about the elements and their uses, from the University of Nottingham

Making the modern world - Polymers and intermolecular bonds
A clear illustrated guide to how new materials now in everyday use were developed, from the Science Museum