The valency of aluminium in AlCl₃ is: MCQ with Answer and Explanation

Question
The valency of aluminium in AlCl₃ is:
A. 4
B. 3
C. 2
D. 1
Answer: Option B
Solution (By JKExamLibrary)
In AlCl₃, aluminium combines with three chlorine atoms. Chlorine has a valency of 1 (needs one electron to complete its octet). By the criss-cross method, Al has valency 3 because it loses three electrons to achieve a stable octet (Al³⁺). Thus, the formula is AlCl₃. Aluminium's electronic configuration is 2,8,3, so it loses three valence electrons. Exam tip: Valency equals the number of electrons lost, gained, or shared to complete octet.
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