Which of the following is the most electropositive element?

$Fe$ is placed in the eighth group of the periodic table. What is the number of electrons in its outermost orbit?

The first $(\Delta_{i} H_{1})$ and the second $(\Delta_{i} H_{2})$ ionization enthalpies (in $kJ \ mol^{-1}$) and the $(\Delta_{eg} H)$ electron gain enthalpy (in $kJ \ mol^{-1}$) of a few elements are given below:

Elements	$\Delta_{i} H_{1}$	$\Delta_{i} H_{2}$	$\Delta_{eg} H$
$I$	$520$	$7300$	$-60$
$II$	$419$	$3051$	$-48$
$III$	$1681$	$3374$	$-328$
$IV$	$1008$	$1846$	$-295$
$V$	$2372$	$5251$	$+48$
$VI$	$738$	$1451$	$-40$

Which of the above elements is likely to be:
$(a)$ the least reactive element.
$(b)$ the most reactive metal.
$(c)$ the most reactive non-metal.
$(d)$ the least reactive non-metal.
$(e)$ the metal which can form a stable binary halide of the formula $MX_{2}$ $(X = \text{halogen})$.
$(f)$ the metal which can form a predominantly stable covalent halide of the formula $MX$ $(X = \text{halogen})$?

Which pair of elements with the given atomic numbers is expected to have similar properties?

Which of the following elements with the given electronic configurations belong to the same group?
$(i)$ $1s^2 2s^2$
$(ii)$ $1s^2 2s^2 2p^5$
$(iii)$ $1s^2 2s^2 2p^6 3s^2 3p^5$
$(iv)$ $1s^2 2s^2 2p^6 3d^{10} 4s^1$

Consider the elements $N$, $P$, $O$, $S$, $Cl$ and $F$. The number of valence electrons present in the elements with most and least metallic character from the above list is respectively.