Question

The valency shell of element $A$ contains $3$ electrons while the valency shell of element $B$ contains $6$ electrons. If $A$ combines with $B$, the probable formula of the compound formed will be

• A. $A{B}_2$
• B. $A_{2}B$
• C. $A_2{B}_3$
• D. $A_3{B}_2$

Answer 1

Answer: (C)

The first element $A$, has $3$ electrons in it's outermost shell, thus it valency is $3$ .
The second element $B$, has $6$ electrons in it's outermost shell, thus it's valency is $2$ .
So the element formed will be $A_2{B}_3$.