John Bransby is a former principal and examiner and is currently a Maths and Science Educational consultant.

Dmitri Ivanovitch Medeleev designed the first Periodic Table in 1871. Since then it has become critical to our understanding of Chemistry and our Universe.

This link will take you to an applet that can help scientists of all levels.
http://collective.chem.cmu.edu/applets/pertable.php

The actual use of this applet in the classroom or at home is quite simple. Simply click on the desired element. Data about the element, as well as a graphical plot of electron configuration and the element’s aufbau diagram will be displayed on the right of the table.

The following video clips are also interesting:
- http://www.youtube.com/watch?v=5MMWpeJ5dn4
- http://www.youtube.com/watch?v=zGM-wSKFBpo