Boxi Learn › Chemistry › Stage 3 · Structure and Evidence
Snap atoms into molecules
CHEM-2 Structure decides propertiesX-1 Guess, then check
What many people think
Atoms can stick together in any number and any way.
The idea
Each atom makes a fixed number of bonds, so only certain molecules can be built.
Explain it
Why can you build H₂O₂ but never H₃O as a neutral molecule? Use the number of bonds each atom makes.
Try at home
Use balls of play dough and toothpicks. Give every ball a fixed number of toothpicks: 1 for H, 2 for O, 3 for N, 4 for C. Which molecules can you build with every toothpick joined?