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1. General Information
- Symbol: Mg
- Atomic Number: 12
- Atomic Mass: 24.305 u
- Group: 2 (Alkaline Earth Metals)
- Period: 3
- Block: s-block
- Electron Configuration: 1s² 2s² 2p⁶ 3s²
- Valence Electrons: 2
- Phase at Room Temperature: Solid
2. Isotopes of Magnesium
| Isotope | Protons | Neutrons | Abundance | Notes |
|---|---|---|---|---|
| ²⁴Mg | 12 | 12 | 79% | Most abundant. |
| ²⁵Mg | 12 | 13 | 10% | Stable. |
| ²⁶Mg | 12 | 14 | 11% | Stable, used in dating rocks. |
3. Physical Properties
- Color: Silvery-white
- Odor: Odorless
- Density: 1.74 g/cm³
- Melting Point: 650°C
- Boiling Point: 1,090°C
- State at STP: Solid
- Lightweight and Malleable – Can be easily shaped and machined.
4. Chemical Properties
- Highly Reactive (Especially with Water and Acids):
- Reacts slowly with cold water and vigorously with hot water.
- Burns with a bright white flame when ignited.
- Forms a Protective Oxide Layer (MgO): Prevents further corrosion.
- Reacts with Oxygen: Forms magnesium oxide (MgO).
Reaction with Water:
Mg + 2H₂O → Mg(OH)₂ + H₂↑
5. Occurrence and Abundance
- Eighth most abundant element in Earth’s crust.
- On Earth:
- Found in Minerals: Dolomite (CaMg(CO₃)₂), Magnesite (MgCO₃), and Olivine.
- Seawater: Contains magnesium chloride (MgCl₂).
- In the Human Body: Present in bones and cells, crucial for biochemical reactions.
6. Industrial Production of Magnesium
- Electrolysis of Magnesium Chloride (MgCl₂):
MgCl₂ → Mg + Cl₂
- Thermal Reduction of Dolomite:
2CaO + 2MgO + Si → 2Mg + Ca₂SiO₄
7. Uses of Magnesium
| Application | Description |
|---|---|
| Aerospace and Automotive | Lightweight alloys reduce vehicle weight. |
| Construction | Used in structural alloys and beams. |
| Medicine | Magnesium supplements and antacids. |
| Fireworks and Flares | Burns with bright white light. |
| Electronics | Laptop and camera casings. |
| Biological | Essential for muscle function and energy production. |
| Batteries | Used in magnesium-ion batteries. |
8. Important Magnesium Compounds
| Compound | Formula | Use |
|---|---|---|
| Magnesium Oxide | MgO | Refractory bricks, insulation. |
| Magnesium Hydroxide | Mg(OH)₂ | Antacid, laxative (milk of magnesia). |
| Magnesium Sulfate | MgSO₄ | Epsom salt, muscle relaxation. |
| Magnesium Chloride | MgCl₂ | De-icing, dust control, supplements. |
| Magnesium Carbonate | MgCO₃ | Gym chalk, food additive. |
9. Biological Importance of Magnesium
- Essential for Life:
- Involved in Over 300 Enzymatic Reactions.
- Critical for ATP (energy) production and muscle function.
- Bone Health:
- 60% of the body’s magnesium is stored in bones.
- Daily Requirement:
- Men: 400-420 mg/day
- Women: 310-320 mg/day
- Deficiency Symptoms: Muscle cramps, fatigue, and irregular heartbeat.
10. Magnesium in Environmental Chemistry
- Seawater Desalination: Magnesium is extracted as a byproduct.
- Soil Health: Magnesium is a key component of chlorophyll in plants.
- Role in Photosynthesis:
Chlorophyll (C₅₅H₇₂MgN₄O₅)
- Without magnesium, plants cannot produce food through photosynthesis.
11. Safety and Hazards
- Highly Flammable: Burns intensely at high temperatures.
- Water Reaction: Can generate hydrogen gas, posing explosion risks.
- Handling Precautions:
- Store in a dry, cool place.
- Use protective gloves when handling.
- Avoid exposing to open flames.