An element $X$ (atomic number $17$) reacts with an element $Y$ (atomic number $20$) to form a divalent halide.
$(a)$ What will be the nature of oxide of element $Y$? Identify the nature of bonding in the compound formed.
$(b)$ Draw the electron dot structure of the divalent halide.

(N/A) Element $Y$ has an atomic number of $20$,which corresponds to Calcium $(Ca)$. Its electronic configuration is $2, 8, 8, 2$. Since it is a metal,its oxide ($YO$ or $CaO$) will be basic in nature.
The compound formed is $YX_2$ $(CaCl_2)$. Since $Y$ is a metal and $X$ is a non-metal (Chlorine,atomic number $17$),the bonding between them is ionic.
$(b)$ The electron dot structure involves the transfer of two electrons from the outermost shell of $Y$ to two atoms of $X$:
$Y_{\times}^{\times} + 2[\cdot X : ] \rightarrow [Y^{2+} (\times \cdot X : ^{-})_2]$