What is Iodine? | Types, Definition, Structure, Function & Facts
What is Iodine?
Iodine is the fourth element in the seventeenth column of the periodic table. It is classified as halogen and non-metal. The iodine atom has 53 electrons and 53 protons with 7 valence electrons in the outermost shell.
Characteristics and Properties
Under standard conditions, iodine is a blue-black solid. Iodine crystals can sublimate directly from a solid to a gas. As a gas, iodine is a purple vapor.
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Iodine is a fairly active element, but it is slightly less active than the other halogens above it on the periodic table, including bromine, chlorine, and fluorine. Iodine can form compounds with many elements. Some of its most common compounds are formed with sodium and potassium.
Highlights of Iodine:
| Symbol | I |
| Atomic Number | 53 |
| Atomic Weight | 126.904 |
| Classification | Halogen |
| Phase at Room Temperature | Solid |
| Density | 4.933 grams per cm cubed |
| Melting Point | 113.7°C, 236.66°F |
| Boiling Point | 184.3°C, 363.7°F |
| Discovered by | Bernard Courtois in 1811 |
Where is Iodine found on Earth?
Iodine is quite rare, but is found both in the earth’s crust and in the waters of the oceans. In fact, the concentration of iodine in the ocean is higher than in the earth’s crust. Some marine plants such as seaweed have high concentrations of iodine. It is also found in groundwater near oil and natural gas reserves.
How is Iodine used today?
Other uses include animal feed, cloud seeding, dyes and photography.
Iodine is also an essential element for life. It plays an important role in the thyroid gland that controls the body’s growth rate. Too little iodine can lead to growth retardation and slower cognitive development (low intelligence). To make sure people get enough iodine, people often add so-called iodized salt to salt.
How was Iodine discovered?
Iodine was first discovered and isolated by the French chemist Bernard Courtois in 1811. Courtois came across iodine while experimenting with algae. It was the French chemist Gay-Lussac who first named iodine a new element and proposed the name.
Where did Iodine get its name?
Iodine gets its name from the Greek word “iodes” which means “purple”.
Isotopes
Iodine has a naturally occurring stable isotope, iodine-127.
Interesting Facts about Iodine
Many people get the iodine they need from their diet by eating seaweed.
It is the heaviest element necessary for human life and health.
Iodine-rich foods include fish, dairy products (milk, cheese, yogurt), some fruits and vegetables, and iodized salt.
Pregnant women need more iodine than the average person. They can get this through dietary supplements.
Too much iodine is harmful and can make a person very ill. Never take iodine without your doctor’s advice.