Goal
Score more points than the robot. The game ends when every card is in its place on the Periodic Table; whoever has more points wins.
The board
The board is the Periodic Table itself. All the cards start face down and shuffled over the spaces. There are two modes: half table (hydrogen to xenon) and full table (118 elements plus the special cards).
Your turn
Tap two cards to flip them. They match when the two elements are:
- in the same periodic group: one of columns 1 to 18, the lanthanides or the actinides (for example, Na and K, or Nd and Ho); or
- in the same affinity: metalloids, representative metals or transition metals.
Matched: you score and play again, and the cards go to their places in the table, swapping with the ones that were there. No match: the cards close and the turn passes to the robot.
Scoring
Each element is worth its atomic number (Z).
| Situation | Points |
|---|---|
| Same periodic group | (Z₁ + Z₂) × 2 |
| Same affinity only | (Z₁ + Z₂) × 1 |
| Closing a group | +50 |
| Closing an affinity | +25 |
| Closing the game | +1000 |
| An element left alone in its group | Z + bonus |
Special cards
- Hydrogen: worth a flat 1000 points.
- Ln and An: briefly reveal the lanthanides and the actinides and give 1000 points.
- Mendeleev wild cards (×2, ×3, ×5 and ×10): they multiply your next score.
Special cards don't use up your attempt: after flipping one, you keep playing.
The robot
The robot, like you, remembers the cards it has seen, but, like a human, it can get confused and open the wrong card. That is what gives the three levels: easy, normal and hard. On average, the easy robot wins about 30% of the games, the normal one about 50% and the hard one about 70%.
Ranking
In Settings → Ranking you compare your average points, your best score and your wins with those of other players, separately by level and by mode. There is no sign-up: the ranking uses the nickname you choose.