fluorine

Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists as a pale yellow-green gas at standard temperature and pressure. Fluorine is the most electronegative element, meaning that it has a strong tendency to attract electrons. This makes fluorine a very reactive element, and it can react with most other elements.

Fluorine is used in a variety of applications, including:

• Fluoridated water to help prevent tooth decay
• Teflon, a non-stick coating used in cookware
• Stainless steel, a strong and durable alloy
• Hydrofluoric acid, a powerful acid used in etching and cleaning

The toothpaste was fluorinated to help strengthen teeth.