An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be

An element $X$ (atomic number $17$) reacts with an element $Y$ (atomic number $20$) to form a divalent halide.
$(a)$ Where in the periodic table are elements $X$ and $Y$ placed?
$(b)$ Classify $X$ and $Y$ as metal$(s)$,non-metal$(s)$,or metalloid$(s)$.

State whether the following statement is true or false:
$A$ solution of an ionic compound in water contains ions,which move to the opposite electrodes when electricity is passed through the solution.

$A$ compound $Z$ is formed by the transfer of electrons from a metal $X$ to a non-metal $Y$. Identify the type of bond formed in the compound. List three general properties of the compounds formed by such type of bonds.

Write the electron-dot structure for sodium and chlorine atoms. How do these form a chemical bond? Name the type of bond so formed. Why does a compound so formed have a high melting point?

$(a)$ Predict which of the following will form anions and which will form cations:
$(i)$ $Na$ $(ii)$ $Al$ $(iii)$ $Cl$ $(iv)$ $O$
$(b)$ Name two elements that are inert.