Question

Two atoms $X$ and $Y$ have $5$ and $7$ valence electrons. The formula of the compound formed by their combination is:

• A. $XY$
• B. $X{Y}_2$
• C. $X{Y}_3$
• D. $X_{3}Y$

Answer 1

The correct option is C $X{Y}_3$

$X$ - No. of electrons in valence shell - 5

Electrons required for octet configuration - 3 (valency $=3$)

$Y$ - No. of electrons in valence shell - 7

Electrons required for octet configuration - 1 (valency $=1$)
$X⟶3$
$Y⟶1$
$X{Y}_3$
The compound formed by a combination of X and Y is $X{Y}_3$.

Hence, the correct option is $\text{C}$