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1. General Information
- Symbol: Na
- Atomic Number: 11
- Atomic Mass: 22.99 u
- Group: 1 (Alkali Metals)
- Period: 3
- Block: s-block
- Electron Configuration: 1s² 2s² 2p⁶ 3s¹
- Valence Electrons: 1
- Phase at Room Temperature: Solid
2. Isotopes of Sodium
| Isotope | Protons | Neutrons | Abundance | Notes |
|---|---|---|---|---|
| ²³Na | 11 | 12 | 100% | Stable and naturally occurring. |
| ²²Na | 11 | 11 | Trace | Radioactive, used in medicine. |
3. Physical Properties
- Color: Silvery-white
- Odor: Odorless
- Density: 0.97 g/cm³
- Melting Point: 97.8°C
- Boiling Point: 882.8°C
- State at STP: Solid (soft, can be cut with a knife)
- Conductivity: Excellent conductor of electricity and heat.
4. Chemical Properties
- Highly Reactive:
- Reacts vigorously with water to form sodium hydroxide (NaOH) and hydrogen gas.
- Combines easily with halogens to form salts (e.g., NaCl).
- Oxidizes Quickly: Forms a white oxide layer (Na₂O) in air.
- Stored in Oil: Prevents reaction with moisture and air.
Reaction with Water:
2Na + 2H₂O → 2NaOH + H₂↑
5. Occurrence and Abundance
- Sixth most abundant element in Earth’s crust.
- Common Sources:
- Seawater (NaCl) – Primary source of sodium compounds.
- Minerals: Halite (rock salt), soda ash, and cryolite.
- Soil and Rocks – Sodium-containing minerals are widespread.
6. Industrial Production of Sodium
- Electrolysis of Molten Sodium Chloride (NaCl):
2NaCl → 2Na + Cl₂
- Downs Cell Process:
- Sodium is produced by electrolyzing molten NaCl with calcium chloride to lower melting point.
7. Uses of Sodium
| Application | Description |
|---|---|
| Salt (NaCl) | Essential for food and preservation. |
| Glass Production | Sodium carbonate (soda ash) used in glassmaking. |
| Chemical Manufacturing | Produces sodium hydroxide, bleach, and detergents. |
| Batteries | Sodium-ion batteries for energy storage. |
| Metallurgy | Reduces metals from their ores (e.g., titanium). |
| Lighting | Sodium vapor lamps for streetlights. |
| Medicine | Sodium compounds regulate bodily functions. |
8. Important Sodium Compounds
| Compound | Formula | Use |
|---|---|---|
| Sodium Chloride | NaCl | Table salt, food preservation. |
| Sodium Hydroxide (Lye) | NaOH | Soap, paper, cleaning products. |
| Sodium Bicarbonate | NaHCO₃ | Baking soda, antacids. |
| Sodium Carbonate | Na₂CO₃ | Glass production, detergents. |
| Sodium Nitrate | NaNO₃ | Fertilizers, explosives. |
| Sodium Sulfate | Na₂SO₄ | Paper, detergents, textiles. |
9. Biological Importance of Sodium
- Essential for Life:
- Regulates fluid balance and nerve signaling in the body.
- Critical for muscle contractions and blood pressure control.
- Sodium-Potassium Pump (Na⁺/K⁺): Maintains cell membrane potential.
- Daily Requirement: 1,500 – 2,300 mg for adults.
10. Sodium in Environmental Chemistry
- Seawater: Contains 1.08% sodium by mass.
- Salinity Regulation: Sodium ions contribute to ocean salinity.
- Role in Weathering: Sodium compounds break down rocks and minerals over time.
11. Safety and Hazards
- Highly Reactive:
- Reacts violently with water and air.
- Releases flammable hydrogen gas and heat.
- Corrosive in Solution (NaOH): Causes burns upon contact.
- Fire Hazard: Burns with a bright yellow flame when ignited.
Handling Precautions:
- Store in mineral oil or inert gas.
- Use protective gloves and eyewear.
- Ventilation Required – Prevent accumulation of hydrogen gas.
Fun Facts About Sodium:
- Sodium burns with a bright yellow flame – the same color as sodium vapor streetlights.
- Sodium was first isolated by Sir Humphry Davy in 1807 through electrolysis.
- Table salt (NaCl) is the most well-known sodium compound, essential to human health.
- Sodium ions play a crucial role in neural communication and hydration.