The correct order of increasing chemical activity for the given metals is:

Which of the following oxides is most amphoteric?

The type of oxide formed by the element among $Li$,$Na$,$Be$,$Mg$,$B$,and $Al$ that has the least atomic radius is $:$

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

Elements	$\left( \Delta_{i}H_{1} \right)$	$\left( \Delta_{i}H_{2} \right)$	$\left( \Delta_{eg}H \right)$
$I$	$520$	$7300$	$-60$
$II$	$419$	$3051$	$-48$
$III$	$1681$	$3374$	$-328$
$IV$	$1008$	$1846$	$-295$
$V$	$2372$	$8581$	$+48$
$VI$	$738$	$1451$	$-40$

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 $MX_{2}$ ($X =$ halogen).
$(f)$ the metal which can form a predominantly stable covalent halide of the formula $MX$ ($X =$ halogen)?

Match the oxide given in column $A$ with its property given in column $B$.

Column $A$	Column $B$
$(i) \; Na_{2}O$	$(a) \; Neutral$
$(ii) \; Al_{2}O_{3}$	$(b) \; Basic$
$(iii) \; N_{2}O$	$(c) \; Acidic$
$(iv) \; Cl_{2}O_{7}$	$(d) \; Amphoteric$

Which of the following options has all correct pairs?

$Fe x_2$ and $Fe y_3$ are known when $x$ and $y$ are :