{"id":146,"date":"2020-04-09T09:33:14","date_gmt":"2020-04-09T09:33:14","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=146"},"modified":"2023-08-15T16:40:02","modified_gmt":"2023-08-15T16:40:02","slug":"iodine","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/iodine\/","title":{"rendered":"Iodine (I)"},"content":{"rendered":"\n

Iodine (I) is a chemical element with atomic number 53 in the periodic table. It’s a relatively rare element that\u2019s naturally found in Earth\u2019s crust. Accounting for 460 parts per billion in the layers of our planet, iodine is preceded by 60 other chemicals in relation to the natural abundance of elements.\u00a0<\/span><\/p>\n\n\n\n

Classified as a member of the halogens family of elements, this nonmetal substance is the heaviest amongst all halogens. Additionally, iodine has seven valence electrons in the outermost shell of the atom, which makes it the least reactive halogen element.\u00a0<\/span><\/p>\n\n\n\n

Iodine is listed as essential medicine and occurs in three aggregate states: solid, liquid, and gas.<\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Iodine<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
Symbol<\/td>I<\/td><\/tr>
Name<\/td>Iodine<\/td><\/tr>
Atomic number<\/td>53<\/td><\/tr>
Atomic weight<\/td>126.90447 g.mol-1<\/td><\/tr>
Group<\/td>Halogen<\/a><\/td><\/tr>
Period<\/td>5<\/td><\/tr>
Color<\/td>A dark-violet non-metallic substance with a bluish-black hue<\/td><\/tr>
Physical state<\/td>Solid at room temperature. It also has a liquid and a gas form.<\/td><\/tr>
Crystal Structure<\/td>Orthorhombic<\/td><\/tr>
Electronegativity<\/td>2.66<\/td><\/tr>
Density<\/td>4.93 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting point<\/td>114 \u00b0C<\/td><\/tr>
Boiling point<\/td>184 \u00b0C<\/td><\/tr>
Van der Waals radius<\/td>0.177 nm<\/td><\/tr>
Ionic radius<\/td>2.20 (-1) \u00c5<\/td><\/tr>
Atomic radius<\/td>1.32 \u00c5<\/td><\/tr>
Atomic Volume<\/td>25.74 cm\u00b3\/mol<\/td><\/tr>
Isotopes<\/td>37<\/td><\/tr>
Most characteristic isotope<\/td>Iodine-127<\/td><\/tr>
Electronic shell<\/td>[Kr] 4d10 5s2 5p5<\/td><\/tr>
The energy of the first ionization<\/td>1008.7 kJ.mol-1<\/td><\/tr>
Discoverer<\/td>Bernard Courtois<\/td><\/tr>
Year<\/td>1811<\/td><\/tr>
Location<\/td>France<\/td><\/tr>
Pronunciation<\/td>EYE-eh-dine<\/td><\/tr>
Oxidation States<\/td>(\u00b11),5,7<\/td><\/tr>
Uses<\/td>Required in small amounts by humans. Once used as an antiseptic, but no longer due to its poisonous nature.<\/td><\/tr>
Description<\/td>Heavy, colorless, odorless, noble gas<\/a>.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With the periodic table symbol (I), atomic number 53, atomic mass of 126.9045 g.mol<\/span>-1<\/span>, and electron configuration [Kr] 4d<\/span>10<\/span>5s<\/span>2<\/span>5p<\/span>5<\/span>, iodine is a nonmetallic grayish-black substance with a strong odor that forms solid crystals with a metallic luster, as well as a violet vapor. <\/span><\/p>\n\n\n\n

Out of the 53 electrons, seven of them are located in the outer shell of the iodine atom, while 46 remain in the inner shell. Hence, this septivalent element has low reactivity, since it is able to form chemical bonds with only a few other chemicals.\u00a0\u00a0\u00a0<\/span><\/p>\n\n\n\n

It also appears in two other aggregate states: in the forms of gas and liquid. Liquid iodine is a solution that has a characteristic dark purple color, while iodine gas (I2) has a strong purple hue.\u00a0<\/span><\/p>\n\n\n\n

Iodine reaches its boiling point at 184 \u00b0C, while the melting point is achieved at 114 \u00b0C. This member of the halogen family in the periodic table has an electronegativity of 2.5 according to Pauling, whereas the atomic radius according to van der Waals is 0.177 nm. <\/span><\/p>\n\n\n\n

Metallic Properties of the Nonmetallic Element <\/span><\/h4>\n\n\n\n

As a metalloid, iodine has several allotropes that display the metallic properties of this nonmetallic substance when exposed to room temperature. Namely, element 53 is ductile and can be used as a semi-conductor of heat and electricity.\u00a0<\/span><\/p>\n\n\n\n

The metallic characteristics of iodine are most strongly exhibited in the following iodine compounds:<\/span><\/p>\n\n\n\n