[VanNistelrooy]

I have tried a lot but couldn't understand this concept of ionization energies. Now if the first ionization energy of two elements A and B are 500 kJ mol-1 and 375 kJ mol-1 respectively. Comment about their relative positions in a group as well as in a period.Also write what is ioniztion energy. please help if you can.

[Donaldson Tan]

if these two elements are in the same period, then they have different number of protons. the ionisation energy is therefore related to the nuclear charge, and the nuclear charge acting on the valence electrons would therefore be related to the number of protons. of course you must be able to relate to exceptions such as removing electrons frm 2p4 vs 2p3..

[jdurg]

The ionization energy of an element is a measure of how much energy is required to remove an electron from said element in a neutral, ground state.  So the 1st ionization energy is how much energy is needed to make the element have a +1 charge, and the second ionization energy is how much energy is needed to make it have a +2 charge and so on and so on.  So if you know the trends of the elements on the periodic table in terms of the ions they like to form, you should easily be able to figure out where Element A is in comparison to Element B.