History of the periodic table High School tarsia - use as lesson starter, plenary or revision

This is a High School Chemistry tarsia for revision of history of the periodic table. I suggest that the A4 tarsia is printed on card and then the outline is cut out. Students can then quickly cut out the individual triangles. Included are the following topics: nationality of Dobereiner, Newlands and Mendeleev, law of triads, law of octaves, atomic number, gallium, number of natural elements and number of elements known to Mendeleev, grouping of the elements. The 'fjsw' file can be opened and modified with tarsia software that is free to download. Please note that the software does not work on Mac computers.