Iodine
⚕️ In Your World
Iodine is a crucial element for human health, as it is a key component of thyroid hormones that regulate metabolism. To prevent deficiency, it is commonly added to table salt (iodized salt). As a solution (tincture of iodine), it is a powerful antiseptic used to disinfect cuts and wounds. When heated, the solid iodine sublimes into a beautiful violet-colored gas.
📖 The Discovery Story
Iodine was discovered in 1811 by French chemist Bernard Courtois. He was extracting sodium and potassium compounds from seaweed ash. When he added too much sulfuric acid, a cloud of purple vapor was produced, which then crystallized on cold surfaces. He suspected it was a new element, and his work was confirmed by other chemists. It was named "iodine" by Joseph Louis Gay-Lussac from the Greek word iodes, meaning "violet-colored."
📊 Properties at a Glance
| Phase at STP | Solid |
| Melting Point | 113.7 °C / 236.7 °F |
| Boiling Point | 184.3 °C / 363.7 °F (sublimes) |
| Electron Configuration | [Kr] 4d¹⁰5s²5p⁵ |
| Abundance in Earth's Crust | 0.000045% |
⚠️ Safety & Handling
While iodine is an essential nutrient, it can be toxic in large doses. Iodine vapor is an irritant to the eyes and respiratory system. Direct contact with solid iodine can cause skin burns, so it should be handled with care.