Question

The maximum covalency of Aluminum is:

(A) 4

(B) 6

(C) 8

(D) 3

Answer 1

Hint: Covalency is the property of an atom to form a bond by sharing electrons. Basically, covalency is the number of electrons shared by an atom during formation of covalent compounds. Write the electronic configuration of Aluminum. Think about compounds formed by Aluminum to get the answer.

Complete answer:

- Aluminum has the atomic number 13. It belongs to the Boron family, that is, the thirteenth group in the periodic table.

- Aluminum is a metal having the electronic configuration,

 $ {}^{13}Al=1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{1}} $ 

- It has three electrons in its outermost orbit or valence shell. So, Aluminum has three valence electrons. Valence electrons are the total number of electrons present in the outermost shell of an atom.

- Valency is the number of electrons required by an atom to complete its octet to attain the nearest noble gas configuration and become stable. So, the valency of Aluminum is 5.

- Let’s think about some compounds formed by Aluminum.

- Aluminum forms Aluminum trichloride by sharing three electrons with three electrons of three chlorine atoms.

- Similarly, triethylaluminium, trimethyl Aluminum also have three covalent bonds.

- The maximum number of covalent bonds formed by Aluminum is three only.

- Therefore, the maximum covalency of Aluminum is 3.

Hence correct option is (D).

Note: Remember covalency and valency are different terms. Covalency is the number of electrons taking part in formation of covalent compounds whereas valency is the number of electrons required to complete an octet.