Physical & chemical properties, reactivity series, ionic bonding, and extraction of metals
| Property | Metals | Non-Metals |
|---|---|---|
| Physical state | Mostly solid (except Hg liquid) | Solid, liquid, or gas |
| Lustre | Shiny (metallic lustre) | Non-lustrous (except graphite, iodine) |
| Hardness | Hard (except Na, K — soft) | Brittle (except diamond — hardest) |
| Malleability | Malleable (beaten to sheets) | Not malleable (brittle) |
| Ductility | Ductile (drawn into wires) | Not ductile |
| Conductivity | Good conductors of heat and electricity | Poor conductors (except graphite) |
| Melting point | High (except Ga, Cs, Hg) | Generally low |
| Density | Generally high | Generally low |
| Sound | Sonorous (ring when struck) | Not sonorous |
• Mercury (Hg) — metal that is liquid at room temperature
• Sodium & Potassium — metals soft enough to cut with a knife
• Gallium & Cesium — metals with very low melting points
• Iodine — non-metal with metallic lustre
• Graphite — non-metal that conducts electricity
• Diamond — non-metal that is hardest natural substance
4Na + O₂ → 2Na₂O (burns vigorously, stored under kerosene)
2Mg + O₂ → 2MgO (burns with dazzling white light)
4Al + 3O₂ → 2Al₂O₃ (forms protective layer — doesn't corrode further)
2Cu + O₂ → 2CuO (black copper oxide)
Gold, silver, platinum — do NOT react with oxygen (least reactive)
2Na + 2H₂O → 2NaOH + H₂↑ (vigorous, with cold water)
2K + 2H₂O → 2KOH + H₂↑ (so vigorous that H₂ catches fire!)
Ca + 2H₂O → Ca(OH)₂ + H₂↑ (moderate with cold water)
Mg + H₂O → MgO + H₂↑ (only with steam)
Fe + 3H₂O → Fe₃O₄ + 3H₂ (only with steam, red hot)
Cu, Ag, Au → Do NOT react with water
Mg + H₂SO₄ → MgSO₄ + H₂↑
Zn + 2HCl → ZnCl₂ + H₂↑
Fe + H₂SO₄ → FeSO₄ + H₂↑
Cu + HCl → No reaction (Cu below H in reactivity series)
Note: Au, Ag react with aqua regia (3HCl:1HNO₃), not individual acids
Fe + CuSO₄ → FeSO₄ + Cu (iron nail turns copper-coloured)
Cu + ZnSO₄ → No reaction (Cu is less reactive than Zn)
Zn + FeSO₄ → ZnSO₄ + Fe
K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Hg > Ag > Au > Pt
Memory trick: King Nathan Can Mgr(Alpha) Znothing FearNilly, Snails Pbig Huge Cups Hg Against Augustine Pt
Metals tend to lose electrons (form cations: +ve)
Non-metals tend to gain electrons (form anions: –ve)
The electrostatic attraction between cation and anion forms an ionic bond.
Example: NaCl formation
Na → Na⁺ + e⁻ (loses 1 electron)
Cl + e⁻ → Cl⁻ (gains 1 electron)
Na⁺ + Cl⁻ → NaCl (ionic compound)
Least reactive metals (Au, Ag, Pt): Found free (native state) in nature. May just need heating.
Moderately reactive metals (Zn, Fe, Pb, Cu): Found as oxides, sulphides, carbonates. Need reduction with carbon/CO or electrolysis.
Highly reactive metals (Na, K, Ca, Mg, Al): Found as compounds. Extracted by electrolysis of molten compounds.
Fe₂O₃ + 2Al → Al₂O₃ + 2Fe + Heat
Aluminium (more reactive) reduces iron oxide to iron. The intense heat (≈3000°C) welds railway tracks! This is called the thermite process.