It is most easier to remove the electron from
s
p
d
f
As we learnt
Factors affecting I.E -
IE increases as the penetration effect of the electron in different orbitals increases. The order of energy required to remove the electron from s,p,d, and f are
- wherein
f-orbital has the poorest shielding effect, electrons in f-orbital experience least attraction from the nucleus. Hence it is easier to remove an electron from f than s,p & d orbitals.