What would be the nature of oxides formed by the elements on the right-hand side of the periodic table?

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.

''Elements in Periodic Table show periodicity of properties.'' List any four such properties.

The element with atomic number $14$ is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

Name the following:
$(a)$ $A$ metal that can be cut with a knife.
$(b)$ $A$ metal that is liquid at room temperature.
$(c)$ $A$ metal that has $3$ valence electrons.

The atomic number of $Na$ and $Mg$ is $11$ and $12$ respectively and they belong to the same period.
$(a)$ Which one would have smaller atomic size?
$(b)$ Which one would be more electropositive?
$(c)$ To which group would each one belong?