Question

IE1,IE2,IE3 for any element are 450,700,1600 KJ/mole respectively. Calculate no. of valence shell electrons,group no.

Answer 1

It has 2 valence electrons

Because there is sudden change in energy from 700 Kj to 1600 Kj which signifies that now there are outermost 8electrons and to lose one of the electrons we need energy of 1600kJ...