You may have wondered, Why does the periodic table look like that? What is it even used for? What good is it to me? Aside from providing critical values such as atomic mass and number for each element, the periodic table can tell us a lot about properties of elements, and is set up specifically to do so. It can tell us about how electrons are set up around the nucleus, how many valence electrons a particular element has, how big an atom is, and how much it wants to gain or lose electrons. All of these trends are important in understanding interactions of atoms with one another, so it's crucial to grasp the foundation of periodic trends first.
The pages to the left are set up in the most logical sequence from top to bottom, so go back to that order if you get lost in a concept. The last page has some sample problems for you to work through to test your understanding of these periodic trends. Interactive animations that may be useful supplements to this website can be found here: http://highered.mcgraw-hill.com/sites/0072396814/student_view0/chapter8/elearning_session.html