Periodic Table

Fluorine

Halogen

Quick Facts about Fluorine

O
  • gas- state of matter at room temperature
  • Stable- has at least one stable isotope
  • -1- common oxidation states in compounds
  • MCL- crystal structure, atomic arrangement in solid form
Ne

Fluorine (F) is element 9 on the periodic table. Atomic mass of F: 18.9980 u. F is in period 2, group 17. Melting point of F: 53.48 K.Density of F: 0.00 g/cm³.

Why Fluorine Matters

The most reactive element—in your toothpaste and non-stick pans

In Your Home

  • Toothpaste (fluoride prevents cavities)
  • Non-stick cookware (Teflon is PTFE)
  • Tap water (often fluoridated)
  • Refrigerants in air conditioners

Industry Uses

DentalFluoride in toothpaste and water prevents tooth decay
ChemicalTeflon and other fluoropolymers for non-stick surfaces
Pharma20% of pharmaceuticals contain fluorine (Prozac, Lipitor)
NuclearUranium hexafluoride (UF6) for uranium enrichment

In Your Body

✗ Not essential

Not essential but beneficial for teeth. Fluoride strengthens enamel by forming fluorapatite. Excessive fluoride causes fluorosis (tooth/bone damage).

Safety: Highly toxic as gas or concentrated compounds. Safe at low concentrations in water (0.7 ppm) and toothpaste.

Discovery of Fluorine

Discovered by Henri Moissan in France, 1886

Name origin: Latin: fluere (flow).

History & Events

1886
Isolation
Henri Moissan finally isolated fluorine after many chemists died trying. Won 1906 Nobel Prize.
1938
Teflon Discovery
Roy Plunkett accidentally discovered Teflon (PTFE) while working on refrigerants
1945
Water Fluoridation
Grand Rapids, Michigan became first city to fluoridate water supply

About Fluorine

A poisonous pale yellow gaseous element belonging to group 17 of the periodic table (The halogens). It is the most chemically reactive and electronegative element. It is highly dangerous, causing severe chemical burns on contact with flesh. Fluorine was identified by Scheele in 1771 and first isolated by Moissan in 1886.

Atomic Properties of F

Atomic Number of F
9
Atomic Mass of F
18.9980 u
Electron Configuration
[He] 2s2 2p5
Electronegativity
3.98
Block
p-block
Group
17
Period
2

Physical Properties of F

Phase (STP)
gas
Melting Point of F
53.48 K
Boiling Point of F
85.03 K
Density of F
0.0017 g/cm3

Thermal Properties

Heat of Fusion
0.51 kJ/mol
Heat of Vaporization
6.54 kJ/mol
Specific Heat
0.82 J/g·K
Molar Heat Capacity
31.30 J/mol·K
Thermal Conductivity
0.03 W/m·K

Atomic Radii

Calculated
50 pm
Covalent
64 pm
Van der Waals
147 pm

Common Misconceptions

Wrong:Fluoride is poison added to water.
Correct:At 0.7 ppm, fluoride prevents cavities safely. Natural fluoride levels can be higher. Dose makes the poison.
Wrong:Fluorine and fluoride are the same.
Correct:Fluorine (F2) is a deadly gas. Fluoride (F-) is an ion found safely in minerals, water, and toothpaste.
Wrong:Teflon is dangerous.
Correct:Teflon is inert and safe. Concerns are about PFOA (manufacturing chemical), not Teflon itself.

Isotopes of Fluorine

Fluorine has 1 naturally occurring isotope, plus 1 notable radioactive isotope.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
189F (F-18)Fluorine-18 isotope18.00093770%109.8 minutesβ⁺, EC
199F (F-19)Fluorine-19 isotope18.99840316100.00%

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Fluorine have important real-world applications in science and industry.

Medical Applications

18F is a radioactive fluorine isotope that is used in an 18F-FDG compound (18F-labeled, fluoro-deoxy glucose) for imaging the organs, bones, tissues, and brain of the body with a technique called positron emission tomography (PET). The 18F-FDG compound is injected and the isotopically labeled glucose is consumed by any cell requiring glucose as a source of energy [98], [99]. – 18F emits positrons that collect in tissue and interact with regular negative electrons when injected into the body. The positrons and electrons annihilate each other, producing two gamma rays that are emitted in opposite directions. The radiation is detected on a PET camera, which generates a picture of the body part being examined (Fig. IUPAC.9.1). –Because 18F has a short half-life of about 110 min, there is little chance of radiation damage to the patient.

Abundance

Earth's Crust
585.0 mg/kg
Seawater
1.3 mg/L

Uses

Used in refrigerants and other fluorocarbons. Also in toothpaste as sodium fluoride (NaF) and stannous fluoride (SnF2); also in Teflon.

Sources

Found in the minerals fluorite (CaF2) and cryolite(Na3AlF6). Electrolysis of hydrofluoric acid (HF) or potassium acid fluoride (KHF2) is the only practical method of commercial production.

Geochemistry

Goldschmidt
litophile
Geochemical Class
semi-volatile

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