What is an amphoteric oxide?

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 $MX$ $(X = \text{halogen})$?

Explain the trends in physical and chemical reactivity of elements across a period and down a group.

The characteristics of elements $X$,$Y$ and $Z$ with atomic numbers,respectively,$33$,$53$ and $83$ are :

The increasing order of reactivity among group-$1$ elements is $Li < Na < K < Rb < Cs$ whereas that among group-$17$ elements is $F > Cl > Br > I$. Explain.

$Br_2 + 2X^{-} \to 2Br^{-} + X_2$
$Cl_2 + 2Y^{-} \to 2Cl^{-} + Y_2$
The incorrect match regarding the above reactions is: