An understanding of the periodic table is central to the study of chemistry. So it is no surprise that it is included in the National Science Education Standards. But how can teachers get students excited about the periodic table? And how can teachers help them learn it in a way that challenges their critical-thinking skills? The authors' experience using Periodic Table Live! (PTL!), together with worksheets they have written to accompany it, indicates that this resource pushes students to think critically and helps them learn the periodic trends in properties. This article describes PTL!, a free, web-based, interactive periodic table, and the worksheets that accompany it. (Contains 1 figure and 4 online resources.)