Question

in these elements Na,Mg,Si and P would have the greatest difference b/w the first and second ionisation enthalpies is
a) Na
b) Mg
c) Si
d) P

Answer 1

It may be Mg because it maximum amount of I.E$x_{2}$ compared to other options.

Answer 2

in the periodic table greatest ionization energy is of noble gasses.
when 1 electron is removed from Na we get noble gas configuration when we remove second electron we need to heigh energy.so for Na difference between first and second ionization enthalpies is greatest.