When the first ionization energies are plotted against atomic number,the peaks are occupied by:

The first $I.E.$ of $Na, Mg, Al$ and $Si$ are in the order:

The electronic configuration of elements $A, B$ and $C$ are $[He] 2s^1, [Ne] 3s^1$ and $[Ar] 4s^1$ respectively. Which one of the following orders is correct for the first ionization potentials (in $kJ \ mol^{-1}$) of $A, B$ and $C$?

The first ionization potentials $\left( eV \right)$ of $Be$ and $B$ respectively are:

The second ionization energy is maximum for

The successive ionization enthalpy values for an unknown element are $\Delta_i H_1 = 899 \ kJ/mol$,$\Delta_i H_2 = 1757 \ kJ/mol$,$\Delta_i H_3 = 14847 \ kJ/mol$,and $\Delta_i H_4 = 17948 \ kJ/mol$. To which group of the periodic table does this element belong?