A Simple Note on What Are Halogens

Halogens are the 5 elements on the periodic table that form a group called Group 7A, and the elements are chlorine, bromine, fluorine, iodine, and astatine. These five elements have special characteristics and properties that make them unique and different from the other elements on the periodic table. Interestingly, these five elements are not found in their elemental form in nature but rather in combination with other nonmetals in molecular form or with various metals in minerals. These elements form salts when they react with metals, and that is because these are highly reactive elements. Further in this article, we will discuss the halogens’ meaning in detail and go through their uses and properties. 

Halogens Elements

It is easy for the elements to pair up to form diatomic molecules as each of the elements has one unpaired electron in their atomic forms. These elements also form compounds with carbon rather easily, wherein the organic molecules that contain carbon are referred to as organohalides or alkyl halides. These halides have several uses in both industrial uses and household uses. 

Fluorine

Fluorine is a gas that looks pale yellow in its elemental form and is highly reactive as well as toxic. It is so toxic that many scientists who tried to isolate the element from its elemental form died young, and their work and death have been illustrated in a book called Asimov on Chemistry. Fluorine is abundantly found in the earth’s crust, and a small amount is also found in seawater, making it the thirteenth most abundant element in the world. 

Chlorine 

This element is a yellow-green gas in its elemental form and is too reactive to be found in nature. It is undoubtedly toxic and is used in bleaches and cleaners; and also used to kill bacteria in drinking water but in the form of sodium hypochlorite. It is produced from the electrolysis of sodium chloride for industrial purposes and is abundant in the earth’s crust, with a small amount present in seawater. It is found in several forms like chloride anions (Cl-) in the mineral halite, and the aqueous solution of hydrogen chloride called hydrochloric acid. 

Bromine

Bromine has a strong smell and is reddish-brown in its liquid form at room temperature. It is the only nonmetal that happens to be in its liquid form at room temperature and is moderately abundant in the earth’s crust. Bromine is found in the form of bromide ion (Br) in bromargyrite ore. This element is mostly used in fire extinguishers and insecticides. 

Iodine 

At room temperature, it forms dark, shiny purple and purple crystals. It is a moderately abundant mineral found in ores of iodargyrite (Agl) and lautarite. It is added to the common salt in the form of potassium iodide (KI), which accumulates in the thyroid gland for incorporation with hormones which regulate metabolic functions. Although it can be toxic if not handled properly, it is not as reactive and dangerous as the previous elements. 

Astatine 

Astatine is not a very abundant element as it is found only in trace amounts. It is a radioactive element found in traces in ore of uranium. The reason for this is its isotopes have short half-lives. 

Halogens Properties

The halogens are reactive nonmetals and have seven valence electrons as pure elements, one short of a stable octet. They form diatomic molecules with atoms by nonpolar covalent bonds when joined. Let us look at some of the halogen’s properties. 

1. Halogens are highly electronegative and highly reactive with alkali metals and alkaline earth. 
2. Halogens are toxic and potentially lethal due to their high level of reactivity. As the halogens get heavier as we go down the list of halogens, the reactivity also decreases, and so does toxicity. However, astatine is considered dangerous for its radioactivity; thus, the level of toxicity may differ from person to person. 
3. Halogens are the only elements present in all the three basic states of solid, liquid, and gas, wherein the state of the matter changes as we go down the list. The top two elements of fluorine and chlorine are gas, the middle one, bromine, is liquid, and the last two, iodine and astatine, are in the form of solid. 
4. Halogens have a relatively weak intermolecular force and can gain an electron by reacting with other elements’ atoms. 
5. These elements have low melting points as well as low boiling points and are also poor conductors of electricity and heat. 

Conclusion

Halogens elements belong to Group 7 on the periodic table and exhibit unique chemical and physical properties. These high reactive nonmetals exhibit colour and odour in their different states or forms and are unstable due to their one short electron to form a stable octet which means they have seven valence electrons. Their high reactivity and toxicity require them to be handled very carefully to avoid causing serious harm to the human body. These are not only harmful to humans but also the ecosystem and the ozone layer, and without control over their usage can cause serious damage to the environment, which goes as far as the ozone layer. Although these are useful for various purposes in households and industries, limiting their usage and exposure is necessary.