The App Cf 98 - Chemistry of post-its presents the periodic table, highlights the elements and contextualizes the creation of post-its and the importance of transforming a chemical experiment that did not work into a product known worldwide. The entire presentation of Cf 98 follows the post-its theme, but without losing scientific rigor and detailed information on the 118 chemical elements of the periodic table. The element CALIFORNIA (Cf 98) and those that were recently discovered, such as Nihonium (Nh 113), stand out.