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.
In contrast, the larger alkali metalsâpotassium, rubidium, and cesiumâreact with oxygen in air to give the metal superoxides. Because the Na cation is intermediate in size, sodium reacts with oxygen to form a compound with an intermediate stoichiometry: sodium peroxide.