Question

Valence electrons in the element $A$ are $3$ and that in element $B$ are $6$ . Most probable compound formed from $A$ and $B$ is

• A. $A_{2} B$
• B. $A B_{2}$
• C. $A_{6} B_{3}$
• D. $A_{2} B_{3}$

Answer 1

Answer: (D)

Valence electron in $A=3$
Valence electron in $B=6$
Thus, $A$ is electropositive and $B$ is electronegative. $A$ can lose three electrons and $B$ can gain two electrons to attain stable configuration.
Thus, $A$ exists as $A^{3+}$ and $B$ as $B^{2-}$ thus, compound is $A_{2} B_{3}$.