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1. General Information
- Symbol: F
- Atomic Number: 9
- Atomic Mass: 18.998 u
- Group: 17 (Halogens)
- Period: 2
- Block: p-block
- Electron Configuration: 1s² 2s² 2p⁵
- Valence Electrons: 7
- Phase at Room Temperature: Gas
2. Isotopes of Fluorine
| Isotope | Protons | Neutrons | Abundance | Notes |
|---|---|---|---|---|
| ¹⁹F | 9 | 10 | 100% | Only stable isotope. |
3. Physical Properties
- Color: Pale yellow
- Odor: Pungent (in gaseous form)
- Density: 1.696 g/L (at STP)
- Melting Point: -219.62°C
- Boiling Point: -188.12°C
- State at STP: Gas
- Molecular Form: F₂ (Diatomic)
4. Chemical Properties
- Most Electronegative Element: 3.98 on the Pauling scale.
- Highly Reactive: Reacts with almost all elements (including noble gases under certain conditions).
- Strong Oxidizing Agent: Pulls electrons from other atoms.
- Reacts Violently with Water: Forms hydrofluoric acid (HF) and oxygen.
- Corrosive and Toxic in elemental form.
Reaction with Water:
2F₂ + 2H₂O → 4HF + O₂
5. Occurrence and Abundance
- Rare as Elemental Fluorine (F₂): Highly reactive, never found free in nature.
- Found in Minerals:
- Fluorite (CaF₂)
- Cryolite (Na₃AlF₆)
- Apatite (Ca₅(PO₄)₃F)
- Earth’s Crust: 0.054% by weight.
6. Industrial Production of Fluorine
- Electrolysis of Hydrogen Fluoride (HF):
2HF → H₂ + F₂
- Source Materials: Fluorite (CaF₂) is used to produce hydrogen fluoride.
7. Uses of Fluorine
| Application | Description |
|---|---|
| Toothpaste and Water Fluoridation | Prevents dental cavities (as fluoride ions). |
| Refrigerants | Hydrofluorocarbons (HFCs), Teflon (PTFE). |
| Medicines | Fluorine-containing drugs (e.g., Prozac, Lipitor). |
| Nuclear Industry | Uranium hexafluoride (UF₆) for uranium enrichment. |
| Metallurgy | Used in aluminum refining (cryolite). |
| Rocket Propellants | Oxidizer in rocket fuel. |
| Non-stick Coatings | Teflon (polytetrafluoroethylene, PTFE). |
8. Important Fluorine Compounds
| Compound | Formula | Use |
|---|---|---|
| Hydrofluoric Acid | HF | Glass etching, metal cleaning. |
| Sodium Fluoride | NaF | Water fluoridation, toothpaste. |
| Uranium Hexafluoride | UF₆ | Uranium enrichment for nuclear power. |
| Sulfur Hexafluoride | SF₆ | Electrical insulator in circuits. |
| Fluoropolymers | PTFE (Teflon) | Non-stick cookware, electrical insulation. |
9. Biological Role of Fluorine
- Not essential for life but important for dental health.
- Strengthens tooth enamel by forming fluorapatite (Ca₅(PO₄)₃F).
- Trace amounts are beneficial; excess can cause fluorosis (tooth discoloration).
10. Fluorine in Environmental Chemistry
- Fluorinated Greenhouse Gases (F-Gases): Potent greenhouse gases like HFCs and SF₆.
- Persistent in Environment: Fluorine-based compounds are chemically stable and hard to break down.
11. Safety and Hazards
- Highly Toxic and Corrosive:
- Fluorine gas can cause severe burns on contact.
- Inhalation is fatal even in small quantities.
- Hydrofluoric Acid (HF): Penetrates skin, causing deep tissue damage and calcium depletion in bones.
- Proper Handling:
- Use protective gloves and eyewear.
- Store in corrosion-resistant containers.
Fun Facts About Fluorine:
- Fluorine is the most reactive element and can react with materials like glass and steel.
- The name “Fluorine” comes from the Latin word “fluere” meaning “to flow”.
- Teflon (PTFE), discovered by accident, is one of the best-known fluorinated materials.
- Fluorine compounds are used in 25% of all pharmaceuticals.