The elements in the Periodic Table are arranged in increasing order of atomic number or nuclear charge. As a result, the pull on the electrons keeps increasing moving left to right. When a new shell is added we start over again at the left. The electrons are further away, and are more easily lost. This process repeats, resulting in the periodic repetition of properties. Because of this, elements are most metallic (lose electrons easily) towards the left and bottom of the table. This Powerpoint presentation examines the distribution of chemical properties on the table based on these trends.
Free worksheets on this topic are available on my website at http://www.evanschemistrycorner.com.