Red hot carbon will remove oxygen from the oxides $XO$ and $YO$ but not from $ZO$. $Y$ will remove oxygen from $XO$. Use this evidence to deduce the order of activity of the three metals $X, Y$ and $Z$ putting the most active first.

Match List-$I$ with List-$II$.

List-$I$ (Oxide)	List-$II$ (Nature)
$A. Cl_2O_7$	$I. \text{Amphoteric}$
$B. Na_2O$	$II. \text{Basic}$
$C. Al_2O_3$	$III. \text{Neutral}$
$D. N_2O$	$IV. \text{Acidic}$

Choose the correct answer from the options given below:

Which element has the greatest tendency to lose electrons?

Which of the following sets of elements have the strongest tendency to form anions?

Given below are two statements:
Statement $I$: The number of pairs among $[Al_2O_3, Cr_2O_3]$, $[Cl_2O_7, Mn_2O_7]$, $[Na_2O, V_2O_3]$ and $[CO, N_2O]$ that contain oxides of same nature (acidic, basic, neutral or amphoteric) is $4$.
Statement $II$: Among $Na_2O, Al_2O_3, CO$ and $Cl_2O_7$, the most basic and acidic oxides are $Na_2O$ and $Cl_2O_7$, respectively.

The basis of keeping the elements in the same group of a periodic table is