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Any of the six nonmetallic elements that make up Group 17 elements of the periodic table are known as halogens. Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At), and Tennessee (Ts) are all halogen elements. The name halogen comes from the Greek word “hal”, which means “salt”, and “gen”, which means “to produce”. All the elements produce sodium salts and have comparable properties. The most well-known of these is sodium chloride known as table salt or halite. This article elucidates the reactivity of group 13 towards halogens and provides notes. 

Occurrences of halogens

As per reactivity of group 13 elements towards halogens, the free halogen elements are not found in nature due to their high reactivity. Fluorine is the most well-known halogen in the earth’s crust in its mixed form. 

The amount of halogens present in the igneous rocks in the earth’s crust is about 0.06 Fluorine, 0.031 Chlorine, 0.00016 Bromine, and 0.00003 Iodine. Elements that are made up of only short-lived radioactive isotopes are Astatine and Tennessee. 

In terms of their chemical properties and the features of their compounds with other elements, the halogen elements are somewhat similar. However, the characteristics of fluorine, chlorine, bromine, and iodine slowly change to astatine.

The difference between two consecutive elements is common with fluorine and chlorine. Fluorine is the most reactive element of halogens, and it has several unique characteristics that distinguish it from the others. 

Uses of halogens

According to the reactivity of group 13 towards halogens, the halogen element chlorine is the most well-known of the elements present in the periodic table. The free element is often used as a water purification agent and in several chemical reactions. 

One of the most well-known chemical compounds is table salt or sodium chloride. Organic fluorides are also used as refrigerants and lubricants. 

Fluorides are commonly added to municipal water supplies to prevent tooth decay. Iodine is best known as an antiseptic, while bromine is mostly used to make bromine compounds. They are also used in flame retardants and pesticides. 

Properties of halogens

All the halogens—that is, fluorine, chlorine, bromine, iodine, and astatine—are nonmetals. These nonmetals make them highly reactive and electronegative. 

Physical properties of halogens

  • Atoms increase as we go down the table because extra electron shells are filled.  
  • The F-F bond is unexpectedly weak when fluorine exists as a diatomic molecule.  
  • Fluorine atoms are the smallest out of all halogens because they are bonded closely. 
  • Due to the increase in strength of Van der Waals forces, the boiling point of halogens increases down the table. 
  • Halogens are the only group that exists in all three states, i.e., gas, liquid as well as solids. 
  • As a form of pure elements, they make diatomic molecules with atoms that are later joined by nonpolar covalent bonds. 

Chemical properties of halogens

  • The chemical properties of halogens are quite stable and uniform. Electronegativity exists within a covalent bond. 
  • It refers to an atom’s ability to attract electrons or electron density towards itself. The force between the nucleus and bonding electrons in the outer shell determines electronegativity. 
  • The number of protons in the nucleus, the distance, and bonding electrons along the shielding effect of inner electrons play a major part in increasing electronegativity. 
  • The H-X bond (hydrogen halides) gets longer as the halogen atoms get bigger. This increases the shielding of inner electrons since the shared electrons are further away from the halogen nucleus. 
  • It also means that electronegativity decreases as we go down the group. 
  • Halogens are particularly reactive with alkaline earth and alkalis. 

Halogen compounds

Halogens are highly reactive, which helps them form hydrogen halides, polygon halogenated compounds, interhalogens, and metal halides. Fluorine is among the most electronegative elements in group 17. 

Reactivity of group 13 towards halogens

All the elements of group 13 of the periodic table react with halogens to form trihalides. All these halides of the element boron are called Lewis acids. 

  • Boron

Boron reacts with halogens like fluorine F2, chlorine Cl2, bromine Br2 thus forming trihalides boron(III) fluoride, BF3, boron(III) chloride, BCl3, and boron(III) bromide, BBr3. 

2B(s) + 3F2(g) → 2BF3(g)

2B(s) + 3Cl2(g) → 2BCl3(g)

2B(s) + 3Br2(g) → 2BF3(l)

  • Aluminium 

AlF3 is aluminium fluoride. This is a compound with a high melting point. Other aluminium halides create molecules with the formula Al2X6 ( where X represents chlorine, bromine, or iodine). A dimer is formed when two AlX3 units (or, more precisely any two identical units) combine to form a molecule. Aluminium halides are called Lewis acids. These have high reactivity.

Conclusion 

Halogens are known as group 17 elements. They contain an unpaired electron in their p orbital. The oxidation state which is common among halogens is -1 because halogens become stable by obtaining just a single electron. The electron which gains becomes halides. This article has provided an insight into the reactivity of group 13 towards halogens.