🔩 Metals and Non-Metals: Complete Concepts & Metallurgy

📑 In This Chapter Guide (Table of Contents)

1. 1. Physical Properties & Notable Exceptions
2. 2. Reactivity Series & Chemical Behavior with Water & Acids
3. 3. Formation & Characteristics of Ionic Compounds
4. 4. Metallurgy: Extraction of Metals from Ores
5. 💡 Frequently Asked Questions (FAQ)

1. Physical Properties & Notable Exceptions

While metals are generally lustrous, malleable, ductile, sonorous, and good thermal/electrical conductors, examiners love testing the critical exceptions:

• Physical State: All metals are solid at room temperature except Mercury (Hg), which is liquid. Among non-metals, Bromine (Br₂) is the only liquid.
• Hardness & Malleability: Alkali metals (Sodium, Potassium, Lithium) are so soft they can be sliced with a butter knife.
• Melting & Boiling Points: Metals have high melting points, but Gallium (Ga) and Caesium (Cs) melt upon contact with the palm of your hand.
• Electrical Conductivity: Non-metals are poor conductors, except Graphite (allotrope of carbon) due to delocalized electrons.
• Lustre: Non-metals are non-lustrous, except Iodine (I₂) crystals which exhibit metallic shine.

2. Reactivity Series & Chemical Behavior with Water & Acids

The reactivity series ranks metals in descending order of their chemical reactivity:

Reactions with Water:

• Potassium & Sodium: React violently with cold water, catching fire due to exothermic H₂ ignition: 2K + 2H₂O → 2KOH + H₂ + Heat.
• Calcium: Reacts with cold water less violently; floats as H₂ bubbles stick to its surface.
• Magnesium: Reacts only with hot water to form Mg(OH)₂ and floats.
• Aluminum, Iron, Zinc: React only with steam: 2Al(s) + 3H₂O(g) → Al₂O₃(s) + 3H₂(g).
• Lead, Copper, Silver, Gold: Do not react with water at any temperature.

Aqua Regia: A freshly prepared mixture of concentrated Hydrochloric Acid and concentrated Nitric Acid in a 3:1 molar ratio. It can dissolve even noble metals like Gold (Au) and Platinum (Pt).

3. Formation & Characteristics of Ionic Compounds

Metals lose valence electrons to form electropositive cations, while non-metals gain electrons to form electronegative anions. The electrostatic attraction between oppositely charged ions forms an Ionic Bond.

Formation of Magnesium Chloride (MgCl₂):

• Magnesium (Z=12, configuration 2,8,2) loses 2 electrons: Mg → Mg²⁺ + 2e⁻.
• Two Chlorine atoms (Z=17, configuration 2,8,7) each accept 1 electron: 2Cl + 2e⁻ → 2Cl⁻.
• Resulting formula: [Mg]²⁺ [ :Cl:⁻ ]₂.

General Properties of Ionic Solids:

1. High melting and boiling points due to strong inter-ionic electrostatic forces.
2. Brittle solids that shatter under mechanical stress.
3. Soluble in polar solvents (water) but insoluble in non-polar organic solvents (kerosene, petrol).
4. Conduct electricity in molten state or aqueous solution (free moving ions), but do NOT conduct electricity in solid state (ions locked in crystal lattice).

4. Metallurgy: Extraction of Metals from Ores

Ores are minerals from which metals can be extracted profitably. Extraction involves 3 stages based on reactivity:

• Roasting vs. Calcination:
  • Roasting: Heating sulphide ores strongly in the presence of excess air to convert them to oxides:
    2ZnS [Zinc Blende] + 3O₂ --[Heat]--> 2ZnO + 2SO₂↑
  • Calcination: Heating carbonate ores strongly in limited air or absence of air:
    ZnCO₃ [Calamine] --[Heat]--> ZnO + CO₂↑
• Thermite Process: Highly exothermic reduction of metal oxides using Aluminum powder as reducing agent. Used for welding railway tracks:
  Fe₂O₃(s) + 2Al(s) → 2Fe(l) [Molten iron] + Al₂O₃(s) + Heat.
• Electrolytic Refining of Copper:
  • Anode: Thick block of impure copper.
  • Cathode: Thin strip of pure copper.
  • Electrolyte: Acidified Copper Sulphate solution (CuSO₄ + dilute H₂SO₄).
  • Pure copper deposits on cathode; insoluble impurities settle below anode as Anode Mud (contains precious metals like Ag, Au).

💡 Frequently Asked Questions (FAQ)

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