Halogen Group

The elements in group 17 are the halogens. The Halogen elements are fluorine, chlorine, bromine, iodine, and astatine. These elements are too reactive to occur freely in nature, but their compounds are cosmopolitan. Chlorides are the foremost abundant; although fluorides, bromides, and iodides are less common, they're reasonably available. During this section, we'll examine the occurrence, preparation, and properties of halogens. Next, we'll test halogen compounds with the representative metals followed by an examination of the interhalogens. This section will conclude with some applications of halogens.

Halogen Group Periodic Table

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Properties of the Halogens

Halogen properties of fluorine could be a pale-yellow gas, chlorine could be a greenish-yellow gas, bromine could be a deep reddish-brown liquid, and iodine could be a grayish-black crystalline solid. Liquid bromine contains a high-pressure level, and therefore the reddish vapour is quickly visible in. Iodine crystals have a standard pressure level. When gently heated, these crystals sublime and form a good-looking deep violet vapour.

Chlorine could be a pale yellow-green gas (left), gaseous bromine is deep orange (centre), and gaseous iodine is purple (right). Fluorine is so reactive that it's too dangerous to handle.

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Bromine is merely slightly soluble in water, but it's miscible altogether proportions in less polar (or nonpolar) solvents like chloroform, carbon tet, and compound, forming solutions that fluctuate from yellow to reddish-brown, counting on the concentration.

Iodine is soluble in chloroform, carbon tet, compound, and lots of hydrocarbons, giving violet solutions of I2 molecules. It's quite soluble in aqueous solutions of iodides, with which it forms brown solutions. These brown solutions result because iodine molecules have empty valence d orbitals and may act as weak Lewis acids towards the iodide ion. 

Halogen Group Numbers 

Fluorine is the most electronegative element within the tabular array. As a result, it's a number -1 altogether. Because chlorine, bromine, and iodine are less electronegative, it's possible to arrange compounds within which these elements have oxidation numbers of +1, +3, +5, and +7, as shown within the table below.

Standard Halogen Group Elements Number

Oxidation Number



CaF2, HCl, NaBr, AgI


F2, Cl2, Br2, I2




HClO2, ClF3


HClO3, BrF5, BrF6-, IF5


HClO4, BrF6+, IF7

Halogens Characteristics

  • All, these elements are incredibly reactive.

  • Due to the present tendency towards high reactivity, the halogens cannot exist within the environment as pure elements. They are usually found occurring as compounds or as ions.

  • Most halogen ions and atoms are often found together with other compounds present within the sea or drinking water. It can be because halogen elements tend to form salt after they are available in contact with the metals and mix with them to make compounds.

  • As mentioned previously, halogens are the sole elemental group within the entire tabular array, which consists of elements that belong to any or all three classical states of matter (solid, liquid, and gas). It can be proven by the fact that when kept under temperature and normal pressure, astatine and iodine take the shape of solids, bromine appears as a liquid, and chlorine and fluorine occur as gases.

  • All halogen elements form hydrogen halides, which are potent acids after they combine with hydrogen and form binary compounds.

  • The halogen group reacts among itself; these elements form diatomic interhalogen compounds.

  • Halogens get their high tendency to react with other matter thanks to high levels of electronegativity of their atoms, which could be a result of the high sufficient nuclear charge of all halogen atoms.

Key Concepts and Summary

The halogens form halides with less electronegative elements. Halides of the metals vary from ionic to covalent; halides of non-metals are covalent. Interhalogens are created by the mixture of two or more different halogens. Minerals are directly reacted by all the representative halogen elements or with solutions of the hydrohalic acids (HF, HCl, HBr, and HI) to provide representative metal halides. Basic anions, like hydroxides, oxides, or carbonates, are involved in the addition of aqueous hydrohalic acids.

FAQ (Frequently Asked Questions)

1. What is the Meaning of Halogen in Chemistry?

The halogens are five non-metallic elements found in group 17 of the tabular array. "Halogen" is also used as a term "salt-former" and Halogens containing compounds are called "salts". The Halogens are Fluorine, Chlorine, Bromine, Iodine, Astatine. All halogens have 7 electrons in their outer shells, giving them several -1. The halogens exist, at temperature, altogether three states of matter:

  • Solid- Iodine, Astatine

  • Liquid- Bromine

  • Gas- Fluorine, Chlorine

2. What are the General Trends in Halogen Chemistry

There are several patterns within the halogen chemistry where neither double or triple bonds are needed to elucidate the chemistry of the halogens. The chemistry of fluorine has simplified the fact it's the first electronegative element within the tabular array and by the fact that it's no d orbitals in its valence shell, so it can't expand its valence shell. Chlorine, bromine, and iodine have valence shell d orbitals and may extend their valence shells to carry as many as 14 valence electrons. Oxidation-reduction reactions conquer the chemistry of the halogens.