Ultrasonic humidifiers are the quietest humidifiers available, and the ideal choice when noise level is a concern (if you are a light sleeper). In general, a warm moisture humidifier will be much quieter than a cool moisture evaporative humidifier.
Iodine is a chemical element with symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black metallic solid at a standard conditions that sublimes readily to form a violet gas. The elemental form was discovered by the French chemist Bernard Courtois in 1811.
growth and metabolic function. Its chemical symbol is I and its atomic number of 53 on the Periodic Table of Elements. Elemental iodine is two iodine atoms bonded together. Iodide is the ion state of iodine, occurring when iodine bonds with another element, such as potassium. In this form,iodine can be ingested or applied topically (such as with povidone iodine, an iodide). So iodine and iodide are simply different expressions of the same element.