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The elements, chlorine, fluorine, iodine, bromine, and astatine (radioactive element), are together known as halogens. The chemical and physical properties of these elements have been studied very carefully and it is found that in physical properties they showed a perfect gradation and they belong to group Vll in the periodic table.  A short note on the general characteristics of the halogen family with the key points regarding halogens is presented in this article.

Key Points of Halogens

  1.   Chlorine plays an important role in human body functioning. It accounts for 0.15% percent of human body weight. The compounds that belong to bromine and chlorine are usually used in sterilisation such as in disinfectants. Moreover, small amounts of halogen such as iodine or bromine are found in halogen lamps.
  2.   For proper functioning of the human body’s thyroid gland, iodine is essential. Thyroid hormones will not be produced if iodine is not there. And this may lead to hypothyroidism.
  3.   Fluoride is found in products such as toothpaste, baby formulas, and vitamin supplements as well as in water open to public consumption. But if fluorine is overly consumed, it may be deadly.
  4.   Polyhalogenated compounds (PHCs) bioaccumulate in human beings and they are highly reactive. Few of the PHCs have carcinogenic and toxic properties. These are used in pest control services and manufactured products.
  5.     Halogen atoms are mostly lipophilic and less water-soluble. Their penetration is improved through tissues and lipid membranes. Some halogen drugs are also accumulated in adipose tissue.

General Characteristics of Halogen Family

  1. Electronic Configuration of Halogen Family: The electronic configuration of the halogen family is ns2np5. There are always seven valence electrons in the halogen family. Rather than having filled outer p and s orbitals, they are one electron less. And this is the reason why they are very reactive.
  2.     Atomic and Ionic Radii of the Halogen Family: The elements of the halogen family usually have the smallest atomic radii in their particular period. This means that they have a larger nuclear effective charge. Atomic and ionic radii of the halogen family increase from the top level to the bottom in a certain group. And, in this way, they increase from fluorine to iodine because of the increasing number of quantum shells.
  3.     Ionisation Enthalpy of the Halogen Family: Halogen having the highest ionisation energy is F as it has the smallest atomic radii. Due to its high and effective nuclear charge, it has a greater tendency to attract and this is the reason why it is not possible to take out the electron from the outer part of the shell of F. Therefore, it has high ionisation energy.
  4.     The Halogen Family is Extremely Reactive: The elements chlorine, fluorine, iodine, bromine, and astatine ( radioactive element) are together known as halogens and all these elements of the halogen family are extremely reactive.

      As the halogen family is highly reactive, they are unable to exist in the environment as pure elements. Usually, they are found occurring as ions or as compounds.

  1.     Most of the halogen ions and atoms are found combined with other compounds that are present in mineral water or sea. This happens because halogens usually create salt as they come in contact with metals and combine the metals to form compounds.
  2.     The family of halogens belongs to the only elemental group in the periodic table. These are composed of elements that belong to three states of matter, namely, liquid, solid, and gas. It is also proved that when iodine and astatine are kept at room temperature, they take the form of solid, fluorine and chlorine appear as gases, and bromine appears as liquids.
  3.     Hydrogen halides are formed due to the halogen family. When hydrogen halides are combined with hydrogen and form binary compounds, a very strong acid is formed.
  4.     If the halogen elements react among themselves within the halogen group, diatomic interhalogen compounds are formed.
  5.     If biological lifeforms are exposed to large quantities of halogens, they may suffer harmful experiences for long durations.
  6.   Due to the high level of electronegativity, halogens can easily react with other matter.

Conclusion

In this article, we have discussed the general characteristics of the halogen family. The elements, chlorine, fluorine, iodine, bromine, and astatine (radioactive element), are together known as halogens. The chemical and physical properties of these elements have been studied very carefully and it is found that in physical properties, they showed a perfect gradation and they belong to group Vll in the periodic table. There are different characteristics of the halogen family. If biological lifeforms are exposed to large quantities of halogens, they may face harmful experiences for long durations. The electronic configuration of the halogen family is ns2np5. There are always seven valence electrons in the halogen family. The halogen having the highest ionisation energy is F as it has small atomic radii . Due to its high and effective nuclear charge, it has a high tendency to attract and this is the reason why it is not possible to take out the electron from the outer part of the shell of F. If the halogen elements react among themselves within the halogen group, diatomic interhalogen compounds are formed.