Question

Which of the above represents the formula for the most common compound of $X$ and $Y$ ? Where $X$ is $Mg$ and $Y$ is $S$.

• A. $X_{2}Y$
• B. $XY$
• C. $X{Y}_2$
• D. $X{Y}_3$
• E. $X{Y}_4$

Answer 1

The correct option is B $XY$

$XY$ represents the formula for the most common compound of $X$ and $Y$. $X$ and $Y$ represent $Mg$ and $S$. Both are bivalent. So they form magnesium sulphide $MgS$ or $XY$.