Why Is Iodine Important in Chemistry? Key Facts for Students
We all are familiar with the ads of Idoine salt that show up during the break on TV. Your favourite TV actor might be endorsing it, and you don’t know. We used to think why Idoine is so important for our bodies, that even actors are asking us to purchase it, and that too in the form of salt. Well, there are several ways Idoine as a food item helps us, but the benefits don’t stop there. Today we are going to talk about one of the most important chemical elements that you use in your daily life.
Idoine is something that we are using from the very beginning in lots of ways when humankind started cooking food on fire. One of the essential chemicals that we need to survive is Iodine, and our bodies can make it on their own. As a result, we have to rely on food items to compensate for Iodine’s deficiency. As a rule, set by the government, there is a tiny amount of Iodine that could be present in food items unless it has been added during the food processing to keep it fresh and ready to eat for a long time.
Food that has been processed comes with more Iodine due to the presence of iodized salt. In addition to this, if you are thinking about how companies are getting Iodine and whether their Iodine is safe to eat or not? Well, the answer is, most of the Iodine comes from the natural resource, which is our oceans, where it found in large amounts in seaweed.
The Iodine atomic number is 53, in its natural occurrence, it is present in the form of dark grey or purplish colour. It is a part of the halogen element in the periodic table. All the halogens show quite a resemblance in their chemical nature, and the same happens when they form a compound in their general chemical behaviour.
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The Iodine was first extracted from the seaweed by French Chemist Dr Bernard Courtois when he tried to burn the seaweed and got violet colour ashes along with sulfuric acid as a by-product of the experiment. He didn’t know what to call this chemical, so he named it “chemical X.” After that, Sir Humphry Davy was going to Italy from Paris, and on his way, he found that “chemical X” is analogous to chlorine and came with the name Iodine, which means violet colour in Greek.
The atomic mass of Iodine is 126.904, and it is the least reactive halogen. Besides this property, it comes second in the list of electropositive halogens. Iodine is also used in photography and dyes, creating several medicines in the field of medical science.
What Is Iodine?
When talking about the Iodine electron configuration, we first need to know what does it mean by electronic configuration. In terms of chemistry, the electron configuration is the arrangement of electrons in different orbits of an atom or given molecule. Now, if we look at the Iodine electron configuration, we will have this, which is written down below.
1s22s22p63s23p63d104s24p64d105s25p5 , 2-8-18-18-7
Also, Iodine symbol is (I), yes, that’s it, this is how you are going to represent Iodine when you are using it to show the chemical reactions between the two compounds and elements.
The (i) element is quite easy to remember, and its oxidation states are -1, +1, +3, +5, and +7. Likewise, the only stable Iodine which occurs naturally on earth is iodine-127. On the other hand, we have an exceptionally useful isotope of Iodine, which is present in the radioactive form, and this isotope is iodine-131.
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The atomic weight of Iodine is 126.9044. The presence of Iodine in seawater is not magnificent, because you can get only 50 mg of Iodine per metric ton of seawater. But seaweeds are the best resource for extracting Iodine, and most of the Iodine that is present in our food comes from there.
Uses of Iodine
The mass of Iodine makes it a unique element for producing images with the help of a piece of metal. As a result, Iodine made it possible for photography to go commercial; this technique was invented by Louis Daguerre in 1839.
In the modern world, we see a lot of commercial Iodine uses, salts such as Iodide are being used as disinfectants and in pharmaceutical companies to produce medicines.
Furthermore, it is used to print inks and dyes and to create a catalyst to speed up the chemical reaction.
Lastly, one of the most common uses of Iodine is in table salt. It is present in the low amount but helps avoid the iodine deficiency that can lead to malfunctioning of the thyroid gland, resulting in swelling of Goitre in the human body.
FAQs on Iodine: Properties, Electron Configuration & Applications
1. What are the fundamental atomic properties of iodine as per the periodic table?
Iodine is a chemical element with the following fundamental properties:
- Symbol: I
- Atomic Number: 53, which means an iodine atom has 53 protons in its nucleus.
- Atomic Mass: Approximately 126.9 u.
- Group: It belongs to Group 17 of the periodic table, known as the halogens.
2. What is the electron configuration of an iodine atom?
The complete electron configuration for iodine (I) is [Kr] 4d¹⁰ 5s² 5p⁵. The electrons in the outermost shell, the fifth shell (5s² 5p⁵), are its seven valence electrons. To achieve a stable octet, it typically gains one electron, explaining its characteristic reactivity as a halogen.
3. What are the key physical properties of iodine at room temperature?
Iodine has several distinct physical properties:
- State: It is a greyish-black, lustrous solid at standard temperature and pressure.
- Sublimation: Upon gentle heating, it does not melt but undergoes sublimation, turning directly into a violet-coloured gas.
- Solubility: It is only slightly soluble in water but dissolves readily in organic solvents like ethanol and chloroform, and in aqueous solutions of potassium iodide.
- Conductivity: It is a poor conductor of heat and electricity.
4. Why is iodine classified as a non-metal despite exhibiting a metallic lustre?
While iodine's shine is a physical property often associated with metals, its chemical classification as a non-metal is based on its overall chemical behaviour. Iodine has a high electronegativity and high ionisation energy, meaning it prefers to gain an electron rather than lose one. It is also a poor conductor of heat and electricity and forms acidic oxides, all of which are defining characteristics of non-metals.
5. What are some of the most important applications of iodine?
Iodine has several critical applications in medicine, health, and industry. Key examples include:
- Antiseptics: An alcoholic solution of iodine, known as tincture of iodine, is widely used to disinfect minor cuts and wounds.
- Nutritional Supplement: Iodine is essential for the thyroid gland to produce hormones. It is added to table salt (iodised salt) to prevent iodine deficiency disorders like goitre.
- Chemical Analysis: It is used in iodometry, a common method of volumetric chemical analysis.
- Catalyst: It serves as a catalyst in various industrial chemical processes, such as the production of acetic acid.
6. How does the chemical reactivity of iodine compare to other halogens like chlorine and bromine?
Iodine is the least reactive of the stable halogens (fluorine, chlorine, bromine, iodine). This is because its oxidising power decreases down the group. Iodine has a larger atomic size and lower electronegativity compared to chlorine and bromine, making it less capable of attracting an electron and oxidising other substances.
7. Why is iodine much more soluble in a potassium iodide (KI) solution than in pure water?
Iodine (I₂) is a non-polar molecule, while water is highly polar, resulting in very low solubility. However, in an aqueous solution of potassium iodide (KI), the iodine molecule reacts with the iodide ion (I⁻) to form the brown-coloured triiodide ion (I₃⁻). This ion is water-soluble, thus significantly increasing the amount of iodine that can dissolve. The reversible reaction is: I₂ + I⁻ ⇌ I₃⁻.
8. What is sublimation, and why does iodine demonstrate this property so readily?
Sublimation is the process where a substance transitions directly from a solid to a gas phase, bypassing the liquid phase. Iodine exhibits this property because the intermolecular forces holding the I₂ molecules together in its crystal lattice are very weak van der Waals forces. Only a small amount of energy, such as gentle heating at atmospheric pressure, is needed to overcome these forces and allow the molecules to escape into the gaseous state.
