Lithium (Li) – The Lightest Metal and Highly Reactive Alkali Element
1. General Information
- Symbol: Li
- Atomic Number: 3
- Atomic Mass: 6.94 u
- Group: 1 (Alkali Metals)
- Period: 2
- Block: s-block
- Electron Configuration: 1s² 2s¹
- Valence Electrons: 1
- Phase at Room Temperature: Solid
2. Isotopes of Lithium
| Isotope |
Protons |
Neutrons |
Abundance |
| ⁶Li |
3 |
3 |
7.5% |
| ⁷Li |
3 |
4 |
92.5% |
- ⁷Li is the most stable and abundant isotope.
3. Physical Properties
- Color: Silvery-white
- Density: 0.534 g/cm³ (Lowest of all metals)
- Melting Point: 180.5°C
- Boiling Point: 1,342°C
- State at STP: Solid
- Soft and Malleable: Can be cut with a knife.
- Lightest Metal: Floats on water.
4. Chemical Properties
- Highly Reactive:
- Reacts vigorously with water to form lithium hydroxide (LiOH) and hydrogen gas (H₂).
- Reacts with oxygen to form lithium oxide (Li₂O).
- Corrodes Quickly in Air – Forms a dull oxide layer.
- Alkali Metal: Very reactive, stored in oil to prevent oxidation.
Reaction with Water:
2Li + 2H₂O → 2LiOH + H₂↑
5. Occurrence and Abundance
- Rare in Earth’s Crust: 0.002% by weight.
- Found in:
- Minerals: Spodumene (LiAlSi₂O₆), Lepidolite.
- Salt Flats (Brine Pools): Extracted from lithium-rich brine.
- Seawater: In trace amounts.
6. Production and Extraction
| Source |
Method |
| Minerals (Spodumene) |
Mining and chemical processing. |
| Brine Pools |
Evaporation and extraction. |
| Seawater |
Experimental extraction methods. |
7. Uses of Lithium
| Application |
Description |
| Batteries |
Lithium-ion (Li-ion) batteries for electronics and EVs. |
| Medicine |
Treats bipolar disorder (mood stabilizer). |
| Alloys |
Strengthens aluminum and magnesium alloys. |
| Lubricants |
Lithium greases withstand high temperatures. |
| Glass and Ceramics |
Increases durability and thermal resistance. |
| Nuclear Industry |
Lithium-6 used in thermonuclear reactions. |
| Air Purification |
Removes carbon dioxide from the air (Lithium hydroxide). |
8. Unique Properties of Lithium
- Flammable in Air – Ignites when exposed to moist air.
- Low Density – Half as dense as water.
- High Electrochemical Potential – Essential for rechargeable batteries.
9. Lithium-Ion Batteries
- Rechargeable and Lightweight – Used in laptops, smartphones, and electric vehicles.
- High Energy Density – Provides longer-lasting power.
- Components:
- Anode: Lithium-based compound.
- Cathode: Typically cobalt, nickel, or manganese oxides.
- Electrolyte: Lithium salt dissolved in a solvent.
10. Safety and Handling
- Highly Flammable: Can ignite in moist air.
- Stored in Oil or Inert Atmosphere: Prevents oxidation.
- Water Reaction Risk: Produces hydrogen gas and heat, potentially explosive.
- Skin Irritant: Can cause burns upon contact.
Fun Facts About Lithium:
- Lithium salts were once used in soft drinks (e.g., 7Up).
- Stars can produce lithium during certain phases of their lifecycle.
- Lithium-ion batteries power over 75% of portable electronics globally.
- Lithium is one of the few metals that floats on water.