Stop 4 of 12 · The path
Bonding — how atoms join
Three joins cover nearly everything: give-and-take (ionic), sharing (covalent), and the metal sea (metallic).
Bench tool
Predict the join
Pick any two elements — the rule sorts them:
Metal + non-metal → ionic. Two non-metals → covalent. Two metals → metallic.
How it works
- Ionic: transfer. Na gives, Cl takes. Ions stack into brittle crystals; conduct when melted or dissolved.
- Covalent: share. H₂, O₂, CH₄. Low melts, soft — pulling molecules apart is easy.
- Metallic: pool. Electrons roam. Conducts, bends, high melts.
Worked examples
Salt shatters. Tap NaCl and planes of like charges line up and repel — brittle.
Sugar melts low. Covalent molecules, weak gaps between them.
Copper bends. Sea of electrons lets layers slide without breaking.
Where it goes wrong
Molecules vs lattices. Water is molecules; salt is one giant lattice — there is no “NaCl molecule”.
Try it at home: salt vs sugar water
Conductivity test. Stir salt into one cup and sugar into another; if you have a battery-and-bulb tester, only the salt water lights it. Ionic salt splits into moving charged pieces while sugar stays whole.
For teachers
Learners think sharing and stealing are the same — probe by asking where the bonding electrons spend their time. Quickest check: ask why salt water conducts but sugar water does not.