Metals and Non-Metals – Chemistry Notes 🧪
1. Introduction
Metals: Elements that are generally hard, shiny, malleable, ductile, good conductors of heat and electricity, and tend to lose electrons to form cations.
Non-Metals: Elements that are usually brittle (if solid), dull, poor conductors of heat and electricity, and tend to gain electrons to form anions.
2. Physical Properties
A. Metals
- Shiny (lustrous) appearance
- Malleable and ductile
- Good conductors of heat and electricity
- High melting and boiling points (except Na, K, Hg)
- Generally dense
B. Non-Metals
- Dull appearance (except iodine)
- Brittle when solid
- Poor conductors of heat and electricity (except graphite)
- Low melting and boiling points
- Low density
3. Chemical Properties
A. Reaction with Oxygen
- Metals form basic oxides: 2Mg + O₂ → 2MgO
- Non-Metals form acidic oxides: C + O₂ → CO₂
B. Reaction with Water
- Reactive metals like Na: 2Na + 2H₂O → 2NaOH + H₂
- Less reactive metals like Fe: Fe + H₂O (steam) → Fe₃O₄ + H₂
- Non-Metals generally do not react with water
C. Reaction with Acids
- Metals react with acids to produce salt and hydrogen: Zn + 2HCl → ZnCl₂ + H₂
- Non-Metals usually do not react with acids
4. Extraction of Metals
Metals are extracted depending on their reactivity:
- Highly reactive metals (Na, K): Extracted by electrolysis of molten salts.
- Moderately reactive metals (Zn, Al): Extracted by reduction of oxides with carbon or electrolysis.
- Less reactive metals (Cu, Ag, Au): Extracted by heating oxides (smelting) or found in native state.
5. Reactivity Series of Metals
From most reactive to least reactive:
K > Na > Ca > Mg > Al > Zn > Fe > Sn > Pb > Cu > Ag > Au
Used to predict reactions with water, acids, and displacement reactions.
6. Uses
Metals:
- Construction (iron, steel)
- Electrical wiring (copper, aluminium)
- Batteries (zinc, lead)
- Coins (copper, nickel)
Non-Metals:
- Making explosives (N, P, S)
- Fertilizers (N, P, K compounds)
- Insulators and lubricants (sulfur, graphite)
- Medicines (iodine)
7. Electrolysis of Molten Salts
Electrolysis is often used to extract highly reactive metals from their molten salts:
- Molten NaCl → Na at cathode, Cl₂ at anode
- Molten Al₂O₃ → Al at cathode, O₂ at anode
8. Displacement Reactions
More reactive metals displace less reactive metals from their salts:
- Zn + CuSO₄ → ZnSO₄ + Cu
- Fe + CuSO₄ → FeSO₄ + Cu
9. Important Notes
- Metals lose electrons to form cations, non-metals gain electrons to form anions.
- Highly reactive metals like Na and K cannot be obtained by heating oxides—they require electrolysis.
- Less reactive metals like Cu, Ag, and Au are found in their native state and require minimal purification.