Illustrated Periodic Table of The Elements – 500 XXL Piece Jigsaw Puzzle (Eurographics)

The whole periodic table, with every element given a little picture of what it actually does out in the world: a lightbulb filament for tungsten, a balloon for helium, and a rather alarming symbol on the radioactive ones.

Colour-coded by group, with the lanthanides and actinides running along the bottom as always. The pieces are XXL, so it suits doing alongside somebody small who asks a lot of questions.