DefinitionQuestion 1 · Recall
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By the end you can define ionic bonding and describe how it forms in sodium chloride, from electron transfer to a giant lattice of ions.
Sodium is a soft metal that fizzes violently in water. Chlorine is a toxic green gas.
Put them together and you get the stuff you sprinkle on chips. The bond that does it is made of nothing but the attraction between opposite charges.
Sodium's electronegativity is 0.9 and chlorine's is 3.2: a difference of 2.3. Chlorine wins so completely that it takes sodium's outer electron.
| atom | ion | |
|---|---|---|
| sodium | 1s² 2s² 2p⁶ 3s¹ (2,8,1) | : 1s² 2s² 2p⁶ (2,8), like neon |
| chlorine | 1s² 2s² 2p⁶ 3s² 3p⁵ (2,8,7) | : 1s² 2s² 2p⁶ 3s² 3p⁶ (2,8,8), like argon |
Ionic bonding
The electrostatic attraction between oppositely charged ions: positively charged cations and negatively charged anions.
The electron transfer makes the ions. The bond is what holds them together afterwards: the attraction between + and −.
Think of the transfer as the introduction and the attraction as the friendship. Nobody says the introduction is the friendship.
Where it breaks: this introduction is what gives the ions their charges. Without the transfer, there'd be nothing to attract.