Ionic vs covalent bonding – atomic models (NaCl, MgO, Cl₂, HCl, H₂O, CO₂, N₂)
ChemistryChemical BondingAges 15–16
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Chemical Bonding
Two atoms approach each other: a metal fully transfers an electron to a nonmetal, forming oppositely charged ions that attract (ionic bonding), or two nonmetals share a pair of electrons (covalent bonding, shifted toward the more electronegative atom if polar). Students pick a molecule and see the electronegativity difference Δχ on a 0.4–1.7 scale, the Lewis structure, and the bond type.
Lesson: Ionic bonding, covalent bonding, electronegativity, and classifying bond types
What it shows
The animation contrasts the two main models of chemical bonding. In ionic compounds such as NaCl and MgO, the metal atom loses electrons completely and the resulting cation and anion are held together by electrostatic attraction. In molecules such as Cl₂, N₂, HCl, H₂O and CO₂, atoms share electron pairs so that each reaches a noble-gas configuration, with single, double or triple bonds. The electronegativity difference Δχ decides the bond type: below 0.4 nonpolar covalent, 0.4 to 1.7 polar covalent, 1.7 or more ionic.
How to use
Pick a Molecule and watch the atoms approach, then either transfer or share electrons. Use Pause and Replay to stop at each stage and discuss it. Switch on Show Lewis structure to link the animation to the dot diagram, and Show electronegativity-difference scale to place the bond on the Δχ scale. Lower the Animation speed for a first viewing, then compare an ionic, a polar and a nonpolar example.
Parameters you can change
- Molecule NaCl (ionic), MgO (ionic), Cl₂ (nonpolar), N₂ (triple, nonpolar), HCl (polar), H₂O (polar), CO₂ (polar double bonds, nonpolar molecule)
- Show Lewis structure
- Show electronegativity-difference scale
- Animation speed 0.5–3 ×
Questions to explore
- Using Δχ, is the bond in HCl nonpolar covalent, polar covalent or ionic?
- How many electrons does each Mg atom transfer to O in MgO, and which ions form?
- Each C=O bond in CO₂ is polar. Why is the CO₂ molecule as a whole nonpolar?
