Question

Two elements $X$ and $Y$ have following electronic configuration
$X=1s^2,2s^{2}2p^6,3s^{2}3p^6,4S^2$ and $Y=1s^2,2s^{2}2p^6,3s^{2}3p^6$
The compound formed by combination of $X$ and $Y$ is

• A. $X{Y}_5$
• B. $X_2{Y}_5$
• C. $X_5{Y}_3$
• D. $X{Y}_2$

Answer 1

Answer: (D)

$X{Y}_2$

Option D is a Correct answer.

Electronic configuration of X is:

$X=1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$ has $2$ electrons more than stable configuration. So this can be written as $X^{2+}$

after removing $2$ eletrcons.

Electronic configuration of $Y$ is:

$Y$ = $1s^{2}2s^{2}2p^{6}3s^{2}3p^5$ has $1$ electron less than stable configuration. So this can be written as $Y^{-}$

after gaining 1 electron

$X^{2+}+2Y^{-}=X{Y}_2$

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$2$ ions of element $Y$ combine with $1$ ion $X$ to give $X{Y}_2$.

The resulting molecule will be stable and will have no net charge.