Which of the following elements has the lowest ionization energy?

Correct increasing order of first ionisation potential is

The correct order of first ionisation enthalpy of group-$13$ elements is

The third ionization energy is maximum for

First and second ionization enthalpies of lithium are $520 \text{ kJ mol}^{-1}$ and $7297 \text{ kJ mol}^{-1}$ respectively. Energy required to convert $3.5 \text{ mg}$ lithium $(g)$ into $Li^{2+}(g)$ [$Li(g) \rightarrow Li^{2+}(g)$] is . . . . . . $\text{kJ}$. (nearest integer) [Molar mass of $Li = 7 \text{ g mol}^{-1}$]

The five successive ionization enthalpies of an element are $800, 2427, 3658, 25024$ and $32824 \ kJ \ mol^{-1}$. The number of valence electrons in the element is