Group 1 Alkali Metals – Properties + Reactions (IGCSE 0620 | O Level 5070 | AQA | Edexcel)
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Group 1 Alkali Metals: Li, Na, K, Rb, Cs, Fr
All have 1 electron in outer shell → form 1+ ions → highly reactive metals
All have 1 electron in outer shell → form 1+ ions → highly reactive metals
Physical Properties & Trends (6-Mark Favourite)
| Property | Trend Down Group 1 | Reason |
|---|---|---|
| Melting point | Decreases (K < Na < Li) | Weaker metallic bonding (larger ion + more delocalised electrons but greater distance) |
| Density | Increases | Atomic mass increases faster than volume |
| Reactivity | Increases (Cs > Rb > K > Na > Li) | Outer electron further from nucleus → easier to lose |
| Softness | Increases | Weaker metallic bonding |
Key Reactions – Memorise These Equations
- With cold water:
2M(s) + 2H₂O(l) → 2MOH(aq) + H₂(g)
(Li slow fizz, Na fast + melts, K violent + lilac flame) - With oxygen:
4Li → 2Li₂O (oxide)
2Na → Na₂O₂ (peroxide)
K, Rb, Cs → KO₂ (superoxide) - With chlorine:
2M(s) + Cl₂(g) → 2MCl(s)
Memorise Group 1 in 60 Seconds – Song Method
Maximum Internal Links (SEO Boost)
- → Cambridge Periodic Table PDF 2025–2027
- → O Level Chemistry Formula Sheet PDF
- → Full Group 1 Notes + Worksheets
- → Cations & Anions Identification Cheat Sheet
- → IGCSE 0620 Solved Past Papers
- → O Level 5070 Solved Past Papers
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