The correct order of metallic character is:

Considering the atomic number and position in the periodic table,arrange the following elements in the increasing order of metallic character: $Si$,$Be$,$Mg$,$Na$,$P$.

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.

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

The periodic table consists of $18$ groups. An isotope of copper,on bombardment with protons,undergoes a nuclear reaction yielding element $X$ as shown below. To which group,element $X$ belongs in the periodic table?
${}_{29}^{83}Cu + {}_{1}^{1}H \rightarrow 6{}_{0}^{1}n + {}_{2}^{4}\alpha + 2{}_{1}^{1}H + X$

Which pair of elements has the same number of electrons in their valence shell$:-$