Four options, one impostor — chemistry edition. Each round names a category from the periodic table ("Which of these is NOT a noble gas?") and shows four candidates; tap the one that doesn't fit. Rounds sweep across noble gases, halogens, alkali metals, room-temperature states, radioactivity and a round of straight-up fake elements.
The traps lean on near-misses: nitrogen sits right next to the noble gases and behaves almost as lazily; silicon shines like a metal but isn't one; and Adamantium has convinced a generation of Marvel fans it's on the table somewhere. Every round ends with a one-line explanation, so each miss files the fact away properly.
How to play
Read the category, then tap the option that does NOT belong in it.
One pick per round — no second guesses, and the correct answer lights up either way.
A short explanation follows every round (why bromine is liquid, why lead is stable).
The timer counts up from your first pick — a stopwatch to race, never a countdown.
"Review rounds" on the results screen replays every question with its explanation.
What counts in this quiz
10 rounds per run, drawn from a wider pool of periodic-table categories and reshuffled each play.
Categories follow standard chemistry: IUPAC group membership, room-temperature states at standard conditions, elements with no stable isotopes for the radioactivity round.
One point per impostor found; a perfect run is 10/10.
What's not included — and why
No borderline cases — elements whose classification is genuinely disputed are simply not used on either side of a round.
No trick isotopes — the radioactivity round is about the element as found in nature, not exotic lab isotopes.
Good to know
Bromine and mercury are the only two elements that are liquid at room temperature.
Marie Curie named polonium after her homeland Poland — hoping the name would draw attention to Poland's fight for independence.
Dmitri Mendeleev predicted gallium and germanium before anyone found them — he left gaps in his 1869 table and described the missing elements' properties in advance.