Students of middle and high school learning the periodic table often need extra time to understand it. I have found many websites that describe the periodic table but the most interactive ones get their attention and they learn faster and retain it in their memory. Grades shoot up automatically since they master the basics.Science fair projects and seminars to be conducted are given in this topic.The following websites were the most successful among many of my students.
Elements of the periodic table
Suggested reading: The Periodic Table Explained