Which of the following atoms is the most electronegative?

On going from right to left in a period in the periodic table,the electronegativity of the elements:

The electronegativity of the following elements increases in the order:

The electronegativity of $C$,$H$,$O$,$N$ and $S$ are $2.5$,$2.1$,$3.5$,$3.0$ and $2.5$ respectively. Which of the following bonds is most polar?

Fluorine is a better oxidising agent than $Br_{2}$. It is due to

Among the following,the pairs of elements having approximately the same electronegativity values are:
$I$. $H$ and $P$
$II$. $Be$ and $Al$
$III$. $N$ and $Cl$
$IV$. $C$ and $P$