1. Iodine - Element information, properties and uses | Periodic Table
Element Iodine (I), Group 17, Atomic Number 53, p-block, Mass 126.904. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and ...
Element Iodine (I), Group 17, Atomic Number 53, p-block, Mass 126.904. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images.

2. Group 7A — The Halogens - The Parts of the Periodic Table
Group 7A (or VIIA) of the periodic table are the halogens: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The name "halogen ...
Information about various chemical compounds and elements
3. Facts About Iodine | Live Science
Apr 18, 2017 · Iodine is classified as a halogen — a subset of very chemically reactive elements (Group 17 on the periodic table) that exist in the ...
Properties, sources and uses of the element iodine.

4. What Is Iodine? | The Chemistry Blog - Chemical Suppliers
Aug 12, 2020 · Classified as a halogen, it is best known as an essential mineral required by the body to make thyroid hormones. However, while its compound ...
Iodine is an essential mineral and a crucial component to thyroid health. By taking a look at its chemistry, we can understand how it functions.

5. Group 17: General Properties of Halogens - Chemistry LibreTexts
Jun 30, 2023 · These five toxic, non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine ...
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

6. 10 Facts About the Element Iodine (Atomic Number 53 or I) - ThoughtCo
May 7, 2019 · It is located beneath fluorine, chlorine, and bromine on the periodic table, making it the heaviest stable element in the halogen group. Thyroid.
Get facts about the element iodine, which is atomic number 53 on the periodic table, with element symbol I.
:max_bytes(150000):strip_icc()/GettyImages-139822531-58ca19c55f9b581d72826250.jpg)
7. Iodine (I) - Periodic Table
Iodine is a chemical element of the periodic table with chemical symbol I and ... group 17 (fluorine group). Iodine is solid at room temperature. Tellurium ...
Iodine is a chemical element of the periodic table with chemical symbol I and atomic number 53 with an atomic weight of 126.904 u and is classed as a nonmetal.
8. What is Iodine? Definitions and Examples - Club Z! Tutoring
Iodine is a chemical element that is represented by the symbol I and has an atomic number of 53. It is a member of the halogen group of elements and is ...
Iodine is a chemical element that is represented by the symbol I and has an atomic number of 53. It is a member of the halogen group of elements and is located in the periodic table in the 17th group and the 5th period.

9. Iodine Element Facts - Chemicool
Iodine is a bluish-black, lustrous solid. Although it is less reactive than the elements above it in group 17 (fluorine, chlorine and bromine) it still ...
Iodine's properties, interesting facts, discovery, videos, images, states, energies, appearance and characteristics.
10. Discovery, Occurrence, Production, Properties and Applications of Iodine
Dec 17, 2012 · Group in periodic table, 17. Group name, Halogen. Period in periodic table, 5. Block in periodic table, p-block. Color, Violet-dark grey, ...
Iodine was first discovered by Barnard Courtois, a French chemist in 1811 while extracting potassium and sodium from seaweed ash. When he accidentally added sulfuric acid, a violet colored cloud evolved from the mass.

11. Iodine: Definition, Symbol, Properties, Sources and Effects - Testbook
May 14, 2023 · Iodine is an element found in group 17 of the modern periodic table. It is the least reactive halogen and has the highest electropositive ...
Iodine an element of group 17. Learn its symbol, colour, valency, physical & chemical properties, uses, sources & environmental and health effects of iodine

12. The Intriguing Element Iodine | Periodic Table - ChemTalk
Iodine, with atomic symbol I, is a nonmetal that lies in group 17 of the periodic table, the halogens. The element iodine lies below bromine, above astatine, to ...
Iodine element makes a bold statement with its dark color and violet vapor. Find out why this element of the periodic table is so interesting.

13. Iodine: Uses, Properties and Interesting Facts
Iodine is the fourth element in Group 17 of the periodic table, appearing after bromine. Elements in Group 17 are referred to as halogens, a name originating ...
What is Iodine? Iodine is a black, shiny, crystalline solid at room temperature and pressure. It is located on the right side of the periodic table with the other halogens. Iodine is currently used in a wide variety of applications ranging from salts, inks, catalysts, photographic chemicals, and LCD displays. Iodine’s Place in the Periodic Table Iodine’s name is derived from the Greek word “iodes,” meaning “violet” because iodine in gaseous form is purple in color. Iodine is the fourth element in Group 17 of the periodic table, appearing after bromine. Elements in Group 17 are referred to as halogens, a name originating from the Greek root “hal-“ which means “salt.” Iodine is the largest and least electronegative of the stable halogens. In general, atomic size increases within a group because more electron shells (i.e. electrons) are present. The elements below iodine in Group 17 are radioactive and not stable, so they are often not considered for comparisons. Properties of Iodine At room temperature elemental iodine is a black, lustrous solid that has a layered structure. In nature it is sometimes found in rock or mineral form, but most often it exists in its anion form, iodide (I–). It is slightly toxic in small amounts, and extremely poisonous in large amounts. Elemental iodine causes sores on the skin, and iodine gas (I2) causes extreme eye irritation. Though iodine is not as reactive as the previous elements in its group (fluorine, chlorine, bromine), it still does form compounds with many other elements and is considered corrosive. Iodine is classified as a solid and nonmetal, though it does display some metallic properties (mainly its lustrous or shiny appearance). Like many nonmetals, iodine is an insulator, so it is a relatively poor conductor of heat and electricity. Physical Properties Iodine’s visibly layered structure derives from the fact that the solid is composed of layered I2 molecules. The gaseous and dissolved forms of iodine are purple in color. A unique property of iodine is that when heated sufficiently it actually sublimes, meaning it goes straight from a solid phase to a gas phase without becoming a liquid. Iodine has the highest melting and boiling points of the halogens. This is caused by iodine’s relatively large size which results in the strongest van der Waals interactions between the molecules of iodine. Like many nonmetals, solid iodine is very brittle (the opposite of ductile). Melting Point: 113.7 °C=236.7 °F=386.9 K Boiling Point: 184.4 °C=363.9 °F=457.6 K Density: 4.933 g cm-3 Phase at Room Temperature: solid Chemical Properties Iodine is only slightly soluble in water and results in a yellow solution. However, iodine is quite soluble in chloroform, carbon tetrachloride (CCl4), and carbon disulfide (CS2), resulting in purple solutions. Iodine is not reactive with air or acids, but because it is just one electron short of a full octet, it will react with many different elements in order to fill its outer shell of electrons. This near octet is also what causes iodine to be quite reactive and corrosive. Iodine is not a good conductor of electricity because its electrons are held strongly in covalent bonds (the bonds between two iodine atoms to form a molecule of iodine, I2). Because of its relatively large size, iodine’s electronegativity is the lowest among the halogens. Oxidation States: -1 Specific Heat: 429 J/kg*K Electronegativity: 2.66 (Pauling scale) Heat of Fusion: 7.76 kJ/mol Heat of Vaporization: 20.9 kJ/mol Electron Configuration: [Kr] 4d105s2 5p5 Isotopes Iodine has only one naturally-occurring isotope: 127I. Therefore, 127I has a natural abundance of 100%. However, 37 isotopes of iodine exist whose half-lives are known, but most of the half-lives are relatively short because the isotopes are not stable. The radioactive isotope I-131 has been used to treat cancerous thyroid glands. The most stable radioactive isotope that exists is an iodine isotope, I-129. It has a half-life of 15.7 million years! Alloys and Allotropes Because iodine reacts quite readily with most metals and is corrosive, it is not generally used in alloys. One allotrope of iodine exists: I2 (diiodine). It’s actually the form that iodine takes when it is a gas, and it is an example of a diatomic gas. Compounds of Iodine Even though iodine is the least reactive halogen, it is still one of the most reactive elements, forming a variety of compounds. Hydrogen iodide (HI) is a gas that reacts with water to yield water and iodine. It doesn’t really have any uses outside of the research lab where it is used in reactions where iodine is intentionally added (iodination) to a molecule. Iodine oxides are the most stable of the halogen oxides that exist because the I-O bond is so strong (due to a relatively large difference in electronegativity between the O and I atoms). Sodium iodide (NaI) and potassium iodide (KI) are used as nutritional supplements and in chemistry research. Nitrogen triiodide (NI3) is an extremely sensitive and explosive substance. Its extreme reactivity is likely caused by the large amount of strain in the chemical structure caused by having three large iodine atoms being held relatively close to each other by a relatively small nitrogen atom. Due to its extreme sensitivity and inability to control its explosions, NI3 can’t be used for any commercial application. Thyroxine (C15H11I4NO4) is the iodine-containing compound (it’s actually a hormone) that the thyroid gland inside our bodies produces. Thyroxine is used by nearly all of the body’s systems; it plays a vital role in heart and digestive function, metabolism, brain development, muscle control, and bone maintenance. If a person’s thyroid does not produce enough thyroxine, he or she is said to have a condition called hypothyroidism. One cause of this condition is poor iodine intake since iodine is necessary for the production of thyroxine. Interesting Facts about Iodine Iodine appears black in its solid form, but it’s actually a very dark blue-purple which complements the fact that iodine gas is purple. Iodine is the heaviest element (and one of the rarest!) that organisms need to survive. Most iodine produced each year is used in livestock feed as a supplement. Iodized salt was first implemented in Michigan in 1924. People who lived along the coasts of the United States got enough iodine simply from living near the ocean and eating seafood. However, it was eventually discovered that people living inland were struggling with goiters (enlarged thyroid) more often due to a deficiency in iodine. In fact, the term “goiter belt” was used to describe the land from the Rocky Mountains to the Great Lakes to western New York. Thyroid hormone is necessary for physical and mental development. Because iodine is vital for the thyroid to synthesize the hormone thyroxine, a lack of iodine intake before birth (by the mother) or during childhood can result in mental impairment or reduced growth of the child. In fact, congenital hypothyroidism (lacking in thyroid hormone since birth) due to iodine deficiency is the most common preventable cause of intellectual disabilities in the world. Occurrence and Abundance of Iodine Iodine is essential for human life, and we need to consume ~0.1 mg of iodide (I–) every day. Approximately 20 mg of iodine exist within our bodies, mostly in the thyroid gland, which helps regulate hormones and body temperature. This equates to a 0.00002% abundance of iodine in the human body. If we don’t get enough iodine from our diet, the thyroid gland will swell, resulting in goiters. However, you likely don’t have to worry about goiters because have you ever noticed the label on the table salt at home? It likely says “iodized salt” because iodine is added to the table salt (NaCl) in order to make sure we do not become deficient in this element. In nature iodine is commonly found in seawater (in the anion form iodide) in trace amounts (0.000006% abundance), and, accordingly, in seaweed. Historically, seaweed was used as a source of iodine, but now the main source is iodate minerals. Iodate minerals are salt deposits left by the evaporation of ancient seas and salty waters from oil and salt wells. Iodine is mainly produced in Chile and Japan, with some contribution from Russia and the United States. Iodine has only ~0.000049% abundance in the Earth’s crust and 1×10-7% in the universe overall. Uses of Iodine Most Notable Uses in General Iodine was originally used for photography in the production of daguerreotypes which were invented by Louis Daguerre in 1839. Today, we use iodine for several commercial applications. Iodine salts are used in pharmaceuticals and disinfectants. Have you ever seen a yellow solution used as a disinfectant? This is called “tincture of iodine” and gets its yellow color and antiseptic properties from the iodine it contains. It is also used in inks and dyes due to its rich color as well as in human and animal supplements (since it is needed for proper biological function). Finally, it has been used in the polarizing filters of LCD displays. Most Notable Uses in Science In the lab, iodine is primarily used as a catalyst (species used to drive a reaction). It is also used in medicine as an internal contrasting agent for imaging techniques, radiography, and fluoroscopy. Discovery of Iodine Though he nearly lost his claim to fame, Bernard Courtois is the French chemist credited with the discovery of iodine in 1811. He performed experiments using seaweed to produce potassium nitrate (KNO3), an important component of gunpowder being used for the Napoleonic Wars at the time. He added too much sulfuric acid to his product one day and saw purple fumes (remember iodine gas is purple!) which then condensed to form solid, shiny crystals. Courtois had a feeling that these crystals were a new element but didn’t have funding to further study the substance. Therefore, he gave samples of his product to several friends and other chemists, and of those people, Joseph Gay-Lussac and Humphry Davy both independently declared that this was a new element. In fact, Davy sent a letter to the Royal Society of London stating that he had identified (not discovered) a new element, which caused him to mistakenly be named the discoverer. For more than 50 years people thought Davy had discovered iodine before properly attributing credit to Courtois. Iodine in the Future Going forward, uses of iodine in medicine will continue to be studied and implemented, particularly related to cancer treatment and diagnoses. It will continue to be used in supplements to prevent and treat iodine deficiency in humans and animals, as studies have shown that iodine deficiency in adults is still a common problem (affecting approximately two billion people worldwide), just usually not to the extent that goiters form. This has been caused in large part by salt companies not adding sufficient iodine to their product and people cutting salt from their diets for other health reasons.

FAQs
What Group Is Iodine In? ›
iodine (I), chemical element, a member of the halogen elements, or Group 17 (Group VIIa) of the periodic table.
Is iodine a group 17? ›The halogens are located on the left of the noble gases on the periodic table. These five toxic, non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
What is the group and period of iodine? ›Group | 17 | Melting point |
---|---|---|
Period | 5 | Boiling point |
Block | p | Density (g cm−3) |
Atomic number | 53 | Relative atomic mass |
State at 20°C | Solid | Key isotopes |
Iodine is a non-metallic, dark-gray/purple-black, lustrous, solid element. Iodine is the most electropositive halogen and the least reactive of the halogens even if it can still form compounds with many elements.
What are Group 7 elements called? ›The Group 7 elements are called the halogens. They are placed in the vertical column, second from the right, in the periodic table . Chlorine, bromine and iodine are the three common Group 7 elements. Group 7 elements form salts when they react with metals. The term 'halogen' means 'salt former'.
Why is iodine in group 17? ›Halogens are nonmetals with high reactivity. These elements are grouped together as they have similar properties. Group 17 elements, fluorine, chlorine, bromine, iodine, and astatine, are collectively known as halogens (in Greek, halo means salt, and genes mean generating, thus collectively salt-producing).
Is iodine a group 7? ›Group 7A (or VIIA) of the periodic table are the halogens: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
Which element belongs to group 17? ›The element that belongs to group 17 and period 3 is Chlorine and has 3 shells. The electronic configuration of chlorine is Cl → 2 , 8 , 7 .
What are the elements in group 17 called? ›Group 17 elements are called halogens. The name halogens are from Greek halo (sea salt) and gens (producing formation) and thus means 'sea salt former'. Group 17 contains fluorine, chlorine, bromine, iodine which form salts. Hence they are called halogens.
What are the elements in group 17? ›The halogens are located on the left of the noble gases on the periodic table. These five toxic, non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
Is iodine a metal or a metal? ›
Physical and chemical properties. Iodine is a nonmetallic, nearly black solid at room temperature and has a glittering crystalline appearance. The molecular lattice contains discrete diatomic molecules, which are also present in the molten and the gaseous states.
Is iodine a metalloid? ›Iodine may be classified as a metalloid. Lustrous is the property of metals which is shown by Iodine. Iodine shows metallic properties when forming bonds with Fluorine and Chlorine.
Why isn't iodine a metal? ›Iodine is a metalloid. Metalloid elements have one or more allotropes with properties intermediate between those of a metal and a nonmetal. Metals are lustrous, ductile, and conductive of heat and electricity.
What are group 1 metals? ›Group 1A (or IA) of the periodic table are the alkali metals: hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). These are (except for hydrogen) soft, shiny, low-melting, highly reactive metals, which tarnish when exposed to air.
What is group 1 called? ›The Group 1 elements are called the alkali metals. They are placed in the vertical column on the left-hand side of the periodic table . All the Group 1 elements are very reactive . They must be stored under oil to keep air and water away from them.
What belongs to group 17? ›What are halogen elements? The halogen elements are the six elements in Group 17 of the periodic table. Group 17 occupies the second column from the right in the periodic table and contains fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts).
What are group 17 metals? ›The halogens are located on the left of the noble gases on the periodic table. These five toxic, non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
What group is 17 on the periodic table? ›Group 17 is the halogens, they have 7 electrons in their outermost shell. They are all non-metals, and form anions with a -1 charge. Reactivity decreases down the group, with fluorine being the most reactive.