Source: Jennifer Roushar; Images from http://avon-chemistry.com/p_table_lecture.html; www.thesmarticleparticles.blogspot.com; http://en.wikipedia.org/wiki/Periodic_trends; http://en.wikipedia.org/wiki/File:IonizationEnergyAtomicWeight.PNG
Source: http://www.youtube.com/watch?v=ywqg9PorTAw