There are nothing like quizzes to tease, test and train your mind with information you've learned and have yet to learn. Check out FunBased Learning where you can try out several quizzes about the elements and balancing chemical equations. The games aren't timed and you can spend as much time as you like on the problems. You can do them over and over again until you feel your knowledge in each particular area is secure.
There's a site by the Exploratorium that contains all sorts of interesting activities. Among them is an interactive time line available in both flash and HTML versions. You can click on any event or element on the time line and receive pertinent information. For instance, if you click on bismuth you'll find that an unknown alchemist discovered that metal in the 15th Century. It's a great way of learning about not only the nuts and bolts of chemistry, but also the history.
Also on the Exploratorium's website is a puzzle in a printable page format that you can copy and cut out. You are then challenged to assemble the eight negative ions and eight positive ions to form 64 compounds in as many ways as possible. In addition, there's an activity on the site called "What's That Stuff?" which describes the elements that make up such everyday items as toothpaste, paper and bug spray.
On a College of Central Florida website, there's a checker game with a unique twist. Not only does it talk to you in a fun, futuristic voice, but you have to answer a chemistry question correctly before you make any of your moves. And, on a Stetson University site, you can play games of mahjong, where you eliminate tiles by matching a compound tile with the right oxidation tile.