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1. General Information
- Symbol: Al
- Atomic Number: 13
- Atomic Mass: 26.98 u
- Group: 13 (Boron Group)
- Period: 3
- Block: p-block
- Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p¹
- Valence Electrons: 3
- Phase at Room Temperature: Solid
2. Isotopes of Aluminium
| Isotope | Protons | Neutrons | Abundance | Notes |
|---|---|---|---|---|
| ²⁷Al | 13 | 14 | 100% | Only stable isotope. |
| ²⁶Al | 13 | 13 | Trace | Radioactive, used in dating meteorites. |
3. Physical Properties
- Color: Silvery-white
- Odor: Odorless
- Density: 2.70 g/cm³
- Melting Point: 660.3°C
- Boiling Point: 2,470°C
- State at STP: Solid
- Lightweight and Ductile – Can be easily shaped and drawn into wires.
4. Chemical Properties
- Highly Reactive (Forms Oxide Layer):
- Reacts with oxygen to form aluminium oxide (Al₂O₃), creating a protective layer that prevents further corrosion.
- Amphoteric Nature:
- Reacts with both acids and bases.
- Good Conductor of Heat and Electricity.
- Non-Magnetic and Non-Sparking.
Reaction with Oxygen:
4Al + 3O₂ → 2Al₂O₃
Reaction with Hydrochloric Acid:
2Al + 6HCl → 2AlCl₃ + 3H₂↑
Reaction with Sodium Hydroxide:
2Al + 2NaOH + 6H₂O → 2Na[Al(OH)₄] + 3H₂↑
5. Occurrence and Abundance
- Third most abundant element in Earth’s crust (8.1%).
- Never found free in nature – Occurs in compounds.
- Common Ores:
- Bauxite (Al₂O₃·xH₂O) – Primary source of aluminium.
- Cryolite (Na₃AlF₆) – Used in aluminium extraction.
6. Industrial Production of Aluminium
- Bayer Process (Extraction of Alumina):
Bauxite → Al₂O₃ (via caustic soda)
- Hall-Héroult Process (Electrolysis):
Al₂O₃ → Al (Molten Electrolysis with Cryolite)
- Anodes (Carbon) are consumed during electrolysis.
7. Uses of Aluminium
| Application | Description |
|---|---|
| Aerospace and Automotive | Lightweight parts for fuel efficiency. |
| Construction | Window frames, roofing, and structural components. |
| Packaging | Foil, cans, and beverage containers. |
| Electrical Industry | Power lines and cables (light and conductive). |
| Consumer Goods | Laptops, smartphones, and appliances. |
| Transportation | High-speed trains and marine vessels. |
| Medical Equipment | Lightweight surgical tools and equipment. |
8. Important Aluminium Compounds
| Compound | Formula | Use |
|---|---|---|
| Aluminium Oxide | Al₂O₃ | Abrasives, ceramics, refractories. |
| Aluminium Hydroxide | Al(OH)₃ | Antacid, fire retardant. |
| Aluminium Sulfate | Al₂(SO₄)₃ | Water treatment, paper industry. |
| Aluminium Chloride | AlCl₃ | Catalysts in chemical reactions. |
| Aluminium Nitrate | Al(NO₃)₃ | Waterproofing textiles, corrosion prevention. |
9. Biological Role of Aluminium
- No known biological role in humans.
- Non-toxic in small amounts, but excessive exposure may lead to health concerns.
- Used in Medicine:
- Antacids and vaccines (as aluminium salts).
10. Aluminium in Environmental Chemistry
- Recyclable: 75% of aluminium ever produced is still in use.
- Eco-Friendly: Reduces energy consumption by 95% when recycled.
- Environmental Concerns:
- Bauxite mining can cause deforestation and soil erosion.
- Aluminium oxide dust can irritate the respiratory system.
11. Safety and Hazards
- Stable in Air due to the oxide layer.
- Fine Aluminium Dust is Flammable and can explode.
- Health Risks:
- Prolonged exposure to aluminium dust can lead to lung issues.
- Aluminium toxicity is rare but can affect the nervous system.
Handling Precautions:
- Store in a dry place to avoid corrosion.
- Handle aluminium dust carefully to prevent fire hazards.
Fun Facts About Aluminium:
- Discovered in 1825 by Hans Christian Ørsted.
- Once more valuable than gold due to the difficulty of extraction.
- The cap of the Washington Monument is made of pure aluminium.
- Aluminium is used in spacecraft due to its strength-to-weight ratio.