why is the trends in the ionization elements in the periodic table not constant

Question

anonymous · Answer

If I recall correctly the compactness or size of the atom plays a part along with which valence shell the elctrons are being removed from. You'll note the highest ionization is from the smallest atoms in a period when comapring by period. These are also atoms with a complete valence shell that is being ionized.

anonymous · Answer

Lots of different effects cause the energy required for the removal of an electron to be altered. One of the largest changes may be observed in the stepping of sub-shells. When a shell is complete (this may be on the first or a subsequent ionization) the atom/ion is more stable (linearly) and so a greater amount of energy is required to remove one of the electrons. 

Obviously this isn't a full answer (slightly limited by the fact I haven't studied chemistry for around two months, but all of the information above is factually correct and part of the answer) I hope this helped.

anonymous · Answer

yeah