MOST SEARCHED REACTIVITIES

THE METAL ACTIVITY SERIES

1. 1LiLithiumFizzes steadily on water; burns crimson (slower than Na despite its potential)
2. 2CsCaesiumThe most reactive stable metal — ignites in air, explodes in water
3. 3RbRubidiumIgnites in air; reacts explosively with water
4. 4KPotassiumBurns lilac; skims on water with a lilac flame
5. 5BaBariumReacts readily with cold water; burns apple-green
6. 6SrStrontiumReacts with cold water; burns crimson
7. 7CaCalciumSteady fizzing in cold water; burns brick-red
8. 8NaSodiumMelts into a ball and darts across water; burns yellow
9. 9MgMagnesiumVery slow with cold water, rapid with steam; burns brilliant white
10. 10AlAluminiumProtected by a tough oxide layer, so it looks unreactive
11. 11TiTitaniumReactive but passivated — corrosion-resistant in practice
12. 12MnManganeseReacts slowly with cold water, readily with dilute acid
13. 13ZnZincNo cold-water reaction; steady fizzing in dilute acid
14. 14CrChromiumPassivated by its oxide — used for plating
15. 15FeIronRusts in moist air; fizzes slowly with dilute acid
16. 16CdCadmiumSlowly attacked by dilute acids
17. 17CoCobaltOnly slowly attacked by dilute acid
18. 18NiNickelCorrosion-resistant; very slow with dilute acid
19. 19SnTinJust above hydrogen — very slow fizzing with acid
20. 20PbLeadThe last metal above hydrogen — barely reacts with acid
21. 21HHydrogenThe reference point of the whole series
22. 22CuCopperBelow hydrogen — no reaction with water or dilute acid
23. 23AgSilverTarnishes only from sulfur compounds; no acid reaction
24. 24HgMercuryLiquid metal, unreactive with dilute acids
25. 25PtPlatinumNoble metal — only aqua regia attacks it
26. 26AuGoldThe least reactive common metal — found as the free element
27. 27CCarbonReference point for extraction — reduces the oxides of metals below it

Most reactive at the top. Hydrogen and carbon are included as the two reference points for acid reactions and extraction.

RULES WORTH MEMORISING

• Metals above hydrogen displace H₂ gas from dilute acids; metals below it cannot.
• A more reactive metal displaces a less reactive one from its salt solution.
• Metals above carbon are extracted by electrolysis; those below can be reduced with carbon.
• Halogen reactivity falls down the group: F₂ > Cl₂ > Br₂ > I₂.
• The lower the standard reduction potential, the more reactive the metal.