Group: 17 of the periodic table
Elements: Fluorine, chlorine, bromine, iodine, astatine, ununseptium.
Oxidation number: -1
Physical Properties: Brittle (solid), poor conductors of heat and electricity, low melting and boiling points as compared to other non metals
Chemical Properties: Highly reactive and electronegative, seven electrons in the outermost shell
State of Matter: Solid, liquid and gas
'Halogen' was termed by a Swedish chemist Baron Jöns Jakob Berzelius. Halogens are found in the environment only in the form of ions or compounds, because of their high reactivity. The halogen group is composed of six elements, which have many uses in our day-to-day life. We will have a look at these uses in the order they are placed in the periodic table.
Atomic Number: 9
- Fluorine is used in making refrigerants and detergents.
- It is also used mainly for producing sulfur hexafluoride, which acts as a dielectric medium in the electrical industry.
- The most common use of fluorine is as a fluoride in toothpaste. This because it is said to prevent dental cavities.
- In some countries, fluorine is added to the water supply to reduce tooth decay.
- Flourocarbon based compounds are used to prepare anesthetics.
- Liquid fluorine is one of the components that goes into making rocket fuel.
- Fluorinated compounds can be used to create plastic and also for glass etching. They are not only used for decorative etching but also for marking glass bulbs, since they are too thin to be etched.
- Fluoride compounds are present in anti-reflective coatings.
- Fluorine is used as uranium hexafluoride for processing nuclear fuel.
- One of the uses of fluorine is to make Teflon, a non-sticky coating for pans and cookware.
- Earlier, fluorine was used to produce chlorofluorocarbons, and these CFCs were used in aerosol sprays, cleaning agents, and polymers. However, it was found that these compounds can cause ozone layer depletion, and were therefore banned.
Atomic Number: 17
- The most important use of chlorine is as a bleach for manufacturing paper and cloth.
- The most common use of chlorine is for the purification of drinking water and swimming pool water.
- It is also used to treat waste water and sewage.
- Polymer PVC (poly vinyl chloride) is used for making hoses, pipes, and electric cables.
- Chlorine is also used in the production of everyday products such as insecticides, solvents, food paints, and dyes.
- It is used in medicines to treat arthritis, diabetes, and different allergies.
- It is also used in making painkillers, tranquilizers, cough syrups, anticoagulants, and medicines that inhibit the growth of tumors.
- Chlorine is used as a disinfectant, and in cleaning medical labs and kidney dialysis machines.
- It is also used in the manufacturing of protective helmets and equipment for firefighters.
- Bullet-resistant glass and vests contain chlorine.
- Chlorine is also an important element that is used in the preparation of textiles, petroleum products, and paper products.
- Chlorine is also used in bromine extraction.
Atomic Number: 35
- Bromine is also used to disinfect water, as it can kill the bacteria present in water.
- The inorganic form of bromine, silver bromide, is used in photography film.
- Bromine is also used in fumigants and flame proofing agents.
- It is used for producing multicolor dyes for the textile industry.
- Bromine compounds play an important role in the manufacture of pharmaceuticals. Potassium bromide, a compound of bromine, is used in preparing anticonvulsants.
- Bromine is used as an effective pesticide.
- The compounds of bromine, mostly from calcium, sodium and zinc, form a dense water-soluble solution, which is used as a drilling fluid.
- It is also used in coal power plants, to reduce mercury levels.
- 5-bromouracil, a compound of bromine, is used for DNA mutation.
Atomic Number: 53
- Iodine can be used as a water purifying agent.
- It is also used as a sterilizing agent.
- The deficiency of iodine in the human body can lead to 'goiter', a thyroid disease.
- Iodine has been very useful in treating acne, conjunctivitis, cretinism, vaginitis and ovarian problems.
- It is also used as a cough expectorant, and is also helpful in treating allergies, dermatitis, bladder infections, and moles.
- Iodoform, a compound consisting of iodine, is used to treat many conditions like tuberculosis, diabetes, bronchitis, syphilis, and chronic gastric catarrh.
- Iodine acts as an antioxidant in our blood.
- Silver iodide, a compound of iodine, is used in photography.
- Iodine solution is used to test for the presence of starch.
- Another very important use of iodine, since it is quite radio-opaque, is that it can be used as an X-ray radio contrast agent for intravenous injections.
- Besides this, iodine forms many compounds like potassium iodide, which is of commercial use, and as sodium iodide, which is useful in the Finkelstein reaction.
Atomic Number: 85
- Astatine-211 is used as a radioactive tracer.
- It is also used in the treatment of cancer.
Atomic Number: 117
(Note: This is a newly discovered element. Its uses are unknown till date.)
After having a look at the uses, it can be inferred that these reactive elements have been instrumental in making our lives much safer and comfortable. They are very much a part of our day-to-day lives, and are present around us in some form of the other. And not to forget, the halogen lights which are everywhere, and have been lighting up our lives for years now.