Question

The maximum covalency of aluminium is:
A. 4
B. 6
C. 8
D. 3

Answer 1

Covalency is defined as the number of electrons shared through the atoms during the formation of covalent compounds. To find the covalency write the electronic configuration of the aluminium. To get the answer you can also think about the compounds that can be formed by the aluminium.

Complete Solution :
Covalency is defined as the property shown by an atom to form the bond sharing by electrons. Basically we defined covalency as the number of electrons shared through the atoms during the formation of covalent compounds.
- Whereas valency is defined as the number of electrons required by the atoms to complete their octet so they can attain their nearest noble gas configuration and thus become stable.
- In the question we have to find the covalency of aluminium. Aluminium belongs to the group thirteenth of the periodic table that is the Boron family. The atomic number of aluminium is 13 and it is a type of metal. The electronic configuration of aluminium is given as :
$^{13}Al=1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{1}}$

- Here, we can see that the aluminium has three electrons in their valence shell therefore the valence electron of aluminium is 3. Valence electrons are defined as the number of electrons present in the outermost shell of an atom. Now we can say that the valency of aluminum is 5.
- Now, to find the covalency we can think about some of the compounds that are formed by aluminium. Aluminium tends to form aluminium trichloride by sharing three electrons of aluminum with three electrons of chlorine atoms. Similarly, trimethylaluminum and trimethylaluminum also contain three covalent bonds.
- So, we can conclude that the maximum number of covalent bonds that are formed by the aluminium is three.
Therefore, the maximum covalency of aluminium is 3.
So, the correct answer is “Option D”.

Note: Covalency and valency are two different terms. The term covalency is used only for the small elements that can form covalent bonds because the variable valencies are shown by larger elements. So, from the period third the term covalency or valency is replaced by the oxidation number and oxidation state.