Keys: H, C, N, O and L (or 1 to 5) add hydrogen, carbon, nitrogen, oxygen or chlorine, bonded to the selected atom. Tab and the arrow keys pick an atom; Space jumps to an atom with an open slot. B makes, raises or removes the bond between the last two atoms picked. Delete removes the selected atom. Z undoes, X clears, question mark or Shift H gives a hint, M opens the list of molecules. Shift with the arrow keys turns the view. Escape then Tab moves on to the buttons.
🧪 How to play
Pick a molecule. The task gives its name and formula: NH₃ means one nitrogen and three hydrogens.
Add atoms from the palette. A new atom bonds to the selected atom (the one with the orange ring).
Every atom needs a set number of bonds: hydrogen 1, chlorine 1, oxygen 2, nitrogen 3, carbon 4. Yellow studs show the bonding slots still open, and an atom settles when it is full.
Some atoms share two or three pairs of electrons. Pick the two atoms one after the other and press Bond: single, then double, then triple, then none. You can also drag from one atom to the other, or tap a bond.
When your molecule matches, it relaxes into its real 3D shape and shows its shape, a bond angle and a fact. The last group is isomers: the same atoms joined in a different order make a different molecule.
Drag on empty space to turn the molecule; pinch or scroll to zoom. 💡 Hint always suggests the next step, ↩️ Undo takes one back and 🗑️ Clear starts again. Try 🧪 Free build to make anything: the lab names more than 50 molecules. Nothing is saved: ticks for finished molecules last only this visit.
Keys
HCNOL or 1–5
add hydrogen, carbon, nitrogen, oxygen or chlorine (L), bonded to the selected atom
Tab or arrow keys
pick an atom (Space: the next one with an open slot)
B
bond the last two atoms picked: single → double → triple → none
Delete
remove the selected atom (with its hydrogens)
Z · X · ? or Shift+H
undo · clear · hint (plain H adds a hydrogen)
Shift + arrows · +−
turn the view · zoom
M · Esc
list of molecules · let go of the selection (then Tab moves on to the buttons)
What it practises
Covalent bonding as taught at GCSE: how many bonds each atom makes, single, double and triple bonds, turning a formula into a structure, and isomers (ethanol and methoxymethane are both C₂H₆O). The finished shapes add the shapes of molecules and their bond angles from electron-pair repulsion (VSEPR). Angles shown are the ideal ones from that model; real molecules differ by a few degrees.
Molecule Lab