Iodine: Properties, Uses, and Why It Darkens Glasses

The element that when dissolved in alcohol makes a brownish liquid that is used to dress cuts and bruises and is also used in dark glasses is iodine. Iodine is a chemical element with the symbol I and atomic number 53. The element was discovered by the French chemist Bernard Courtois in 1811. Iodine is the heaviest stable halogen and is essential for life. Iodine is used in a variety of applications, including medicine, photography, and water purification.