Commercially, iodine is obtained in several ways, such as taking iodine vapor from processed brine, by ion exchange of brine or by releasing iodine from iodate taken from nitrate ores. It is found in the environment as iodide form.

Drago, R S. Physical Methods For Chemists, (Saunders College Publishing 1992), pp. We'll assume you're ok with this, but you can opt-out if you wish. Solutions with high elemental iodine concentration, such as People can be exposed to iodine in the workplace by inhalation, ingestion, skin contact, and eye contact. We always write 4d before 5s.If we apply the Aufbau principal to the orbitals above, we would predict that the 5s orbital, because it has lower energy than the 4d orbitals, will fill with electrons before the 4d orbitals do – as you’ve said.In fact, when two electrons are present in the 5s orbital the energy of the 4d orbitals falls below the energy of 5s. What I should say to start with is that we’ve followed a convention for electron configurations so that, if there are electrons present in orbitals, lower principal quantum numbers are always shown preceding higher principal quantum numbers in the configuration. The hypoiodite ions thus formed disproportionate immediately to give iodide and iodate:Iodous acid and iodite are even less stable and exist only as a fleeting intermediate in the oxidation of iodide to iodate, if at all.Many periodates are known, including not only the expected tetrahedral They are thermodymically and kinetically powerful oxidising agents, quickly oxidising MnWhen iodine dissolves in strong acids, such as fuming sulfuric acid, a bright blue The only important polyiodide anion in aqueous solution is linear Many other polyiodides may be found when solutions containing iodine and iodide crystallise, such as Organoiodine compounds have been fundamental in the development of organic synthesis, such as in the Some drawbacks of using organoiodine compounds as compared to organochlorine or organobromine compounds is the greater expense and toxicity of the iodine derivatives, since iodine is expensive and organoiodine compounds are stronger alkylating agents.Iodine is the least abundant of the stable halogens, comprising only 0.46 The caliche was the main source of iodine in the 19th century and continues to be important today, replacing These sources ensure that Chile and Japan are the largest producers of iodine today.About half of all produced iodine goes into various organoiodine compounds, another 15% remains as the pure element, another 15% is used to form The iodide and iodate anions are often used for quantitative volumetric analysis, for example in Cesium iodide and thallium-doped sodium iodide are used in crystal Elemental iodine is used as a disinfectant either as the element, or as the water-soluble The antimicrobial action of iodine is quick and works at low concentrations, and thus it is used in operating theatres.Inorganic iodides find specialised uses. Iodine was discovered by Bernard Courtois in 1811 in France. This, rather surprisingly, produced a purple vapor, which condensed into dark crystals. Iodine is an element in group 17/7A on , therefore it is a halogen, and halogens are nonmetals. Elemental iodine is also used as a disinfectant. These were the first crystals of iodine ever made.Courtois studied this new substance and found that it combined well with phosphorous and hydrogen, but it did not form compounds easily with carbon or oxygen.He also discovered that when mixed with ammonia it formed a brown colored solid (nitrogen triiodide) that exploded at the slightest touch.
Although it is less reactive than the elements above it in group 17 (fluorine, chlorine and bromine) it still forms compounds with many other elements. The elements of group 17 are called as Halogens.

The exceptions are decidedly in the minority and stem in each case from one of three causes: extreme inertness and reluctance to participate in chemical reactions (the Given the large size of the iodide anion and iodine's weak oxidising power, high oxidation states are difficult to achieve in binary iodides, the maximum known being in the pentaiodides of Lower iodides may be produced either through thermal decomposition or disproportionation, or by reducing the higher iodide with hydrogen or a metal, for example:Most of the iodides of the pre-transition metals (groups 1, 2, and 3, along with the Hypoiodous acid is unstable to disproportionation.
The element Iodine belongs to the 'Group 17′ in the periodic table. ; Siemens, W.D. For example, while chlorine gas will halogenate At room temperature, it is a colourless gas, like all of the hydrogen halides except Nearly all elements in the periodic table form binary iodides. A solution containing potassium iodide (KI) and iodine in alcohol is used to disinfect external wounds. Furthermore, iodination of metals tends to result in lower oxidation states than chlorination or bromination; for example, rhenium metal reacts with chlorine to form rhenium hexachloride, but with bromine it forms only rhenium pentabromide and iodine can achieve only rhenium tetraiodide. The configuration we’ve shown is actually correct. Therefore, the correct configuration for iodine is [Kr] 4d10 5s2 5p5The reason we don’t always get the result we’d expect from applying the Aufbau Principal to orbitals is that when real electrons begin to interact with one another, some shifts in orbital energy levels can take place.Thanks for the interesting comment Jessica – it may be worth considering whether we continue to show configurations using the principal quantum number convention or whether we show the actual configuration, when it’s known.