Question

Why is second ionisation energy of alkali metals higher than alkaline earth metals?

Answer 1

Alkali metals do not posses second ionization energy because it only has it only posses one valence electron  and the  2nd and third ionization  ionization possesed only based on the valency e.g group 2 elements will only posses 1st and 2nd ionization energy . The higher the valency e.g +2, the higher the amount of energy required to remove the valence electron to change the gaseous atom to the a gaseous ion.