Elemon

Elemon is a free browser card game that turns the periodic table into collectible monsters. All 118 elements are cards, there is an Elemondex, and moves are tied to real science facts. You battle a computer trainer on Easy, Normal or Hard, or play a friend, with no chat.

There is no sign-up, no download, no ads and no in-game currency, and it works on phone, tablet and desktop. A learn section, printable element cards and a teachers section sit alongside the battles.