The Hill system (or Hill notation) is a system of writing empirical chemical formulas, molecular chemical formulas and components of a condensed formula such that the number of carbon atoms in a molecule is indicated first, the number of hydrogen atoms next, and then the number of all other chemical elements subsequently, in alphabetical order of the chemical symbols.
Iodine clock reaction. The iodine clock reaction (STd3) is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. Two colourless solutions are mixed and at first there is no visible reaction.
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.