sci_chem
Ionic Bonding
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
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Chemistry · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
A full outer shell (the octet) is the stable, low-energy state. Metals have only 1-3 outer electrons that are easy to lose; non-metals are 1-3 electrons short and gain to fill up.
Sodium (2,8,1) loses 1 electron to become Na⁺ (2,8). Chlorine (2,8,7) gains 1 electron to become Cl⁻ (2,8,8). Both now have full shells.
In solid NaCl this is not a single pair: each Na⁺ is surrounded by 6 Cl⁻ and each Cl⁻ by 6 Na⁺, building a giant 3D lattice.
Breaking the whole lattice needs lots of energy, so melting points are high. Ions are locked in a solid (no conduction) but free when molten or dissolved (conducts).
Hard words & meanings
| ion | an atom that has gained or lost electrons, so it carries a net charge |
| cation | a positive ion, formed when a metal atom loses electrons |
| anion | a negative ion, formed when a non-metal atom gains electrons |
| ionic bond | the electrostatic attraction between oppositely charged ions |
| lattice | a giant, regular 3D arrangement of ions held by electrostatic forces |
| electrostatic attraction | the force of attraction between opposite charges |
| octet rule | atoms tend to bond so they end up with 8 electrons in the outer shell |
| dot-and-cross diagram | a drawing using dots and crosses to show where bonding electrons come from |
Model exam answers, grammar & audio
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