Which pair of elements has the same chemical properties?

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.

Why do elements in the same group have similar physical and chemical properties?

Which of the following orders is correct $-$

The correct order of decreasing acidic nature of oxides is:

In $s-$block,on moving down the group,the reactivity of metals with water and air increases. Which of the following factors has no significance for this trend of reactivity?