The point of the game is to use an abreviation of an element from the periodic table or to use a chemical formula and the person after you has to guess and leave their riddle.
Person 1: SiO₂
Person 2: Citrine Quartz! Po
Person 3: Polonium! Fe
And so on, so on.
Tip: Search up a periodic table to find the definitin of these elements, put them together on the search bar and your answer is there.