Why chromium and copper have exceptionally high Ionisation enthalpies ?

Why noble gases have very high values of ionisation enthalpies ?

Why noble gases have very high values of ionisation enthalpies?

In a period from Li to F ionisation enthalpy

Why 5d transition series elements have higher ionization enthalpies than 4d transition series elements ?

The second ionisation enthalpies of both chromium and copper are higher than those of the next element. Why?

How would you account for the irregular variation of ionisation enthalpies (first and second) in the first series of the transition elements?

The first ionisation enthalpy of nitrogen is higher than that of oxygen but the second ionisation enthalpy is higher in oxygen than that of nitrogen. Explain

Which of the following has highest ionisation enthalpy? P , N , As , Sb .