Molecular Scrabble

Molecular Scrabble is a tile-based word game for 2–4 players, played on a Scrabble-style board. Instead of spelling ordinary words, players place element tiles (each printed with a periodic-table symbol) to spell out valid chemical formulas — real molecules and compounds — earning points based on atomic mass and board bonuses.

The goal: build the highest-scoring, most chemically valid set of molecules before the tile bag runs empty.

• 1 game board (15×15 grid, same bonus-square layout as classic Scrabble)
• 120 Element Tiles, each showing an element symbol (H, O, Na, Cl, Fe, etc.) and a small point value in the corner
• 4 tile racks
• 1 cloth tile bag
• 1 Master Molecule Reference Card (lists valid formulas — see §4)
• 1 scorepad
• This instruction book

Score the most points by building valid molecular formulas on the board using your element tiles — left to right or top to bottom, just like Scrabble words — while landing on bonus squares and using clever combinations of common and rare elements.

A valid play is any sequence of element tiles that forms a real, recognized chemical formula — a compound that actually exists and is charge-balanced.

When in doubt, players check the Master Molecule Reference Card or an agreed chemistry reference — a periodic table plus a basic valence chart works for most home games. Groups may also agree beforehand whether to allow a companion app or printed chemistry dictionary as the "dictionary" equivalent.

Subscript numbers aren't placed as tiles — instead, place the same element tile repeated the correct number of times in a row. So H₂O uses two H tiles and one O tile in sequence.

Points are loosely based on how rare or heavy the element is — common, light elements are worth less, rare or heavy ones are worth more, the same logic as letter frequency in ordinary Scrabble.

120 tiles total, including 4 blank "Wild Isotope" tiles that can represent any element — like a blank in Scrabble.

Same layout as a standard Scrabble board:

1. Place the board in the center of the table.
2. Put all 120 tiles into the bag and shake to mix.
3. Each player draws 7 tiles to fill their rack, keeping them hidden from opponents.
4. Determine turn order (youngest chemist goes first, or draw tiles — closest to H on the periodic table goes first).
5. Place the Master Molecule Reference Card face-up where all players can consult it.

On your turn, do one of the following:

A. Play a formula

• Place tiles to spell a valid chemical formula, either starting fresh (crossing the center square on the first move) or building off tiles already on the board, sharing at least one tile with an existing formula.
• All tiles played in a single turn must form one continuous line, horizontal or vertical.
• Any new formulas incidentally formed by intersecting tiles must also be valid compounds.
• Draw back up to 7 tiles from the bag.

B. Exchange tiles

Return any number of tiles to the bag, shuffle, and draw the same number of replacements. This uses your whole turn — no scoring.

C. Pass

Skip your turn if you can't or don't want to play. If all players pass twice in a row, the round ends early.

1. Add up the point values of every tile in the newly placed formula.
2. Apply any Letter bonus squares to individual tiles first.
3. Apply any Word bonus squares to the total.
4. Add the Biology Bonus (+5) if using that house rule and applicable.
5. If you use all 7 tiles in a single turn, add a +15 "Full Reaction" bonus — the equivalent of Scrabble's Bingo bonus.
6. Record the total on the scorepad.

The game ends when one player uses all their tiles and the bag is empty, or all players pass consecutively twice in a row.

Final scoring adjustment: each player subtracts the point value of any element tiles remaining on their rack. The player who emptied their rack first adds the total value of everyone else's remaining tiles to their own score.

The player with the highest final score wins.

• Organic Chemistry Mode — only carbon-based compounds count as valid plays.
• Ion Rules — allow charged species (Na⁺, Cl⁻) as connectors, worth double points, but the resulting formula must still be neutral overall.
• Teach & Challenge — a player may challenge a formula before the next turn begins. If invalid, the tiles are removed and the turn is forfeited; if valid, the challenger loses their next turn.
• Speed Lab — add a 60-second sand timer per turn.
• Junior Chemist Mode — restrict play to the first 20 elements and simple compounds (H2O, CO2, NaCl, O2, CH4, NH3) for younger or beginner players.

A sample of common molecules to get you started:

A full Master Reference Card with 100+ compounds is included in the box; groups are encouraged to expand it with any real compound they can justify.