Students connect element circles to build correct chemical formulas before time runs out in this fast-paced chemistry puzzle. Five compound targets appear with countdown timers; learners drag through adjacent elements to collect the exact atoms needed, in any order, to complete each compound like H2O, CO2, or NaCl. This activity supports TEKS 8.5.B and Chemistry C.6.D (chemical formulas and bonding).
Skills: chemical formulas, element identification, working under time pressure, accuracy. Grades 8-12.