Wire atoms together into the molecule the round demands, every bond must respect valence, then nudge an equilibrium in the direction it asks for.
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How to play
Rounds alternate between two challenges. In build rounds you assemble a target molecule from loose atoms; in equilibrium rounds you tip a reversible reaction the required way using levers, applying Le Chatelier's principle.
Click two atoms on the grid to bond them, respecting each element's valence.
Right-click a bond to split it if you wired the wrong connection.
A build is complete when the formula matches and every atom's valence is satisfied.
In equilibrium rounds, toggle levers (concentration, temperature and more) to shift the reaction toward the goal.
Controls
Desktop: left-click two atoms to bond, right-click a bond to split, click levers to shift equilibrium; Daily/Practice and New in the bar.
Phone & tablet: tap two atoms to bond and tap levers, note that splitting a bond uses right-click, so a mouse is handy for build rounds.
Tips & strategy
Count remaining valence before bonding, carbon wants four links, oxygen two, hydrogen one.
Build the carbon skeleton first, then cap the dangling bonds with hydrogen.
For Le Chatelier rounds, remember that adding a reactant or removing a product drives the reaction forward, and heat behaves like a reagent for endothermic reactions.
What you'll learn
Reactor blends molecule construction with equilibrium reasoning, grounded in real valence rules and conservation.
Skills: chemistry, chemical equilibrium, valence, conservation of mass
Best for: roughly grades 10–12 (ages 15+)
For parents & teachers: chemical equilibrium and bonding.
Origins
Alternating between assembling molecules and tipping a reversible reaction is chemical equilibrium alongside structure.
Pairing the two is the original design.
Equilibrium is the idea that a reaction does not simply finish. Le Chatelier's principle says a system at equilibrium shifts to partly oppose whatever you do to it, so adding reactant, removing product or changing pressure moves the balance — which is how industrial chemistry gets yields it would not otherwise have.
About Reactor
Reactor blends molecule construction with equilibrium reasoning, grounded in real valence rules and conservation of mass. It's an original, free browser game with a six-round run plus daily and practice modes.
A free, original browser game on PlayPendium. No download, no install.
