Question

why do the first and the second ionisation energies of group 14 elements decrease from carbon to tin whereas , the third and the fourth ionisation energies vary irregularly.

Answer 1

ionization enthalpy decreases in a group because as we proceed from up to the down the attraction of the valence electrons from the nucleus decreases. thus the energy required to move the valence electrons is less.the third and fourth ionization energies vary because the removal of 4electrons from carbon is not possible although it is possible for Some elements in the group 14 that are below carbon