* Symbol: F

* Atomic number: 9

* Atomic weight: 18.9984032

* Electron configuration: 1s2 2s2 2p5

* Valence electrons: 7

* Oxidation states: -1, 0, +1, +2, +3, +4, +5, +6, +7

* Electronegativity: 4.0 (Pauling scale)

* Ionization energy: 1680 kJ/mol (first), 3374 kJ/mol (second), 6050 kJ/mol (third), 8408 kJ/mol (fourth)

* Covalent radius: 71 pm

* Ionic radius: 133 pm (F-)

* Melting point: −219.62 °C

* Boiling point: −188.12 °C

* Density (at 25 °C): 1.696 g/L

* Color: Pale yellow

Physical Properties

Fluorine is a pale yellow, diatomic gas at room temperature. It is the lightest of the halogens and the most reactive element on the periodic table. Fluorine gas is corrosive, toxic, and can form explosive mixtures with certain materials.

Chemical Properties

Fluorine is the most reactive of all the elements and it can react with almost any other element except for the noble gases. Fluorine reacts with all metals to form fluorides, and it reacts with most non-metals to form covalent compounds. Fluorine is also known for its ability to form stable polyatomic ions, such as fluorides (F-), bifluorides (HF2-), and trifluorides (F3-).

Uses

Fluorine is used in a variety of applications, including:

* Production of uranium hexafluoride (UF6), which is used in the enrichment of uranium for nuclear fuel and weapons.

* Production of hydrofluoric acid (HF), which is used in the semiconductor industry, glass etching, and metal cleaning.

* Production of fluorinated polymers, which are used in a variety of applications, such as non-stick cookware, electrical insulation, and medical devices.

* Fluoridation of drinking water, which helps to prevent tooth decay.

Hazards

Fluorine is a hazardous material that can cause serious health problems, including:

* Burns: Fluorine gas can cause severe burns to the skin and eyes.

* Respiratory problems: Inhalation of fluorine gas can cause respiratory problems, such as bronchitis and pneumonia.

* Bone damage: Fluorine can damage bones and teeth, leading to conditions such as osteoporosis and fluorosis.

* Cancer: Fluorine has been linked to an increased risk of certain types of cancer, such as lung cancer and bladder cancer.

Precautions

To protect against the hazards of fluorine, workers must take the following precautions:

* Wear personal protective equipment, such as gloves, goggles, and a respirator.

* Work in a well-ventilated area.

* Store fluorine gas in a safe container in a cool, dry place.

* Follow all safety procedures when working with fluorine.