Writing in the latest issue of the Journal of Chemical Education (2008, 85, 585-589), Scerri explains how the periodic table initially arose from the discovery of atomic weight triads but now suggests that chemists should recognize the fundamental importance of atomic number triads. This would enhance the periodic table by classifying the elements at a fundamental level as basic substances. He has developed a new version of the "left-step" periodic table, which looks very different from the conventional PT having a step-like pattern with actinides and lanthanides forming the first step and climbing to alkali metals and alkaline earth metals on the right. "I am modifying it to accommodate two atomic number triads which would otherwise be absent. They are He, Ne, Ar which ceases to exist as a triad in the usually encountered left-step table and H, F, Cl which does not exist either in the conventional medium-long form table or the usually encountered left-step table," Scerri explains.