The elements chlorine, fluorine, iodine, bromine, and astatine (the radioactive element) are together known as halogens. The chemical and physical properties of these elements have been studied very carefully. Halogens show a perfect gradation and belong to group Vll in the periodic table. In addition, halogens can gain an electron by reacting with atoms of other elements. Fluorine is one of the most reactive elements in existence. 

List of Elements of Halogen Family

There are five elements of the halogen family:

• Chlorine (Cl)
• Fluorine (F)
• Iodine (I)
• Bromine (Br)
• Astatine (At)

Properties of Halogen

As a family, halogen exhibits highly variable physical properties:

• They can gain an electron by reacting with atoms of other elements. 
• At room temperature, halogen ranges from solid (I2) to liquid (Br2) to gaseous (F2 and Cl2). 
• They also form diatomic molecules as pure elements combined with atoms joined by nonpolar covalent bonds. 
• Usually, halogens are highly electronegative. 
• Among all the elements, fluorine is one of the most reactive elements to exist on the planet. 
• Halogens are more reactive with alkaline earth and alkali metals that form a stable type of ionic metals.

Chemical Properties of Halogen

• The chemical properties of halogens are as follows:
• All halogens’ molecules are homonuclear diatomic. This means that, with two atoms, these halogens molecules exist.
• Fluorine is considered the most reactive element among the other halogens that exist.
• Halogens gain atoms when they react with other elements’ atoms.
• There are seven valence electrons of the halogens. As halogens miss one electron, they are highly reactive and can form negative ions.
• Halogens are comparatively weak intermolecular forces.
• The alkylation of amines is a kind of organic reaction between ammonia and alkyl halide. The name of this reaction is nucleophilic aliphatic substitution.

Important Features of the Halogen Family

Let’s find out the important characteristics of the halogen family:

• The electronic configuration of the halogen family is ns2np5. There are always seven valence electrons in the halogen family. Rather than having a filled outer p and s orbitals, they are one electron less. And this is the reason they are very reactive.
• 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. In this way, they increase from fluorine to iodine because of the increasing number of quantum shells.
• The halogen with the highest ionisation energy is fluorine, as it has small atomic radii. Due to its high and effective nuclear charge, it has a high tendency to attract. Thus, it is not possible to take out the electron from the outer part of the shell of fluorine. Therefore, it has high ionisation energy.
• 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.
• Most halogen ions and atoms combine with other compounds present in mineral water or the sea. This happens because halogens usually create salt when they come into contact with metals. They combine with the metals to form compounds.
• The family of halogens belongs to the only elemental group in the periodic table. These are composed of elements belonging to three classical states of matter: liquid, solid, and gas. When iodine and astatine are kept under room temperature, they take a solid form. Fluorine and chlorine appear as gases, and bromine appears in the liquid form.
• Hydrogen halides are formed due to the halogen family. When hydrogen halides combine with hydrogen and form binary compounds, they become very strong acids.
• If the halogen elements react among themselves within the halogen group, they form diatomic interhalogen compounds.
• If biological lifeforms are exposed to large quantities of halogens, they may face harmful experiences. They are toxic, reduce air quality, and can lead to respiratory diseases.
• Due to the high level of electronegativity, the atom’s halogens get their high tendency and can easily react with other matter. And this is the result of a highly effective nuclear charge of all types of halogen atoms.

Conclusion

Here, we have discussed the chemical properties of halogens, along with compounds of halogens. Halogen exhibits highly variable physical properties. They can gain an electron by reacting with atoms of other elements. They also form diatomic molecules as pure elements in combination with atoms that are joined by nonpolar covalent bonds. 

Usually, halogens are highly electronegative. Among all the elements, fluorine is one of the most reactive elements in existence.