Imagine that we were able to communicate with aliens from a parallel universe. Amongst the information that we manage to exchange and translate into our scientific language is a table containing some of the physical and chemical properties of the twelve elemental substances that the aliens claim constitute their world (see Table 1).
Although the aliens have identified some periodic trends in the behaviour of these chemical elements, they have not derived a classification scheme similar to our periodic table. Curious about the possibility of identifying an equivalent pattern, various teams of chemists begin to analyse the information. You have been assigned to one of these teams and your task is to collaborate in the analysis of the available data to characterize any existing physical and chemical trends and, if possible, derive the corresponding periodic law.
Source: Talanquer, V.A. (2005). Recreating a Periodic Table: A Tool for Developing Pedagogical Content Knowledge.