Sheppard Software provides free interactive learning games on the web. Kids can use the "Periodic Table" game to learn more about each element by clicking on its corresponding symbol on the periodic table. The game offers five different skill levels from beginner to master level play. Every skill level requires additional knowledge about the elements, from their location on the periodic table to their atomic weight.
Funbrain offers "Proton Don," a quiz game based on the periodic table of the elements. The entire table is shown on the screen, and the quiz master asks you to press the symbol for an element. Right and wrong answers are tracked on a scoreboard. The game offers various levels from beginner to advanced.
Jefferson Lab offers online flashcards of the elements. The basic options allow you to choose the number of questions, the test material and whether or not the answer must be correctly capitalized. Advanced options let you pick the exact elements you want on the flash cards.
YouTube is an amazing resource for just about anything. Though you do have to sort through some low-quality videos, you can find some great stuff about the elements, including Tom Lehrer's "The Elements" song or They Might Be Giants' "Meet the Elements."