Arrange the following as per the instruction given in the bracket
$\mathrm{C}\mathrm{l}, \mathrm{F}, \mathrm{B}\mathrm{r}, \mathrm{I}$ (Increasing order of electron affinity).

Element $\mathrm{X}$ is a metal with a valency $2,\mathrm{Y}$ is a non-metal with a valency $3$.

(i) Write an equation to show how $\mathrm{Y}$ forms an ion?

(ii) If $\mathrm{Y}$ is a diatomic gas, write an equation for the direct combination of $\mathrm{X}$ and $\mathrm{Y}$ to form a compound.

Note: In this table, $\mathrm{H}\mathrm{}$ does not represent hydrogen. Some elements are given in their own symbol and position in the periodic table while others are shown with a letter.
With reference to the above table answer the following questions.
(i) Identify the most electronegative element.

(ii) Identify the most reactive element of group $1$.

(iii) Identify the element from period $3$ with the least atomic sizes.

(iv) How many valence electrons are present in $\mathrm{Q}$?

(v) Which element from group $2$ would have the least ionisation energy?

(vi) Identify the noble gas of the fourth period.