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

after removing $2$ eletrcons.

Electronic configuration of $Y$ is:

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

after gaining $1$ electron

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

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

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