Elements having highest I.P value is :

The electronic configuration of the given element is:

Ne : [He]2s²2p⁶

He : 1s²

Be: 1s²2s²

N : [He]2s²2p³

Although Ne, He and N all have fully filled stable configuration but the electron is to be removed from a '1s' shell in case of He. ;1s' shell being closest to the nucleus makes quite tough to remove an electron from it. Thus, the element having the highest I.P. value is Helium.