Hi, I am slightly confused with the term, ionization energy (IE). I am stuck between two definitions, one is the minimum energy to remove an outermost electron from an atom while the other is the energy to completely remove an electron from ground state. If its the former, wouldn't it have a higher potential energy than that of the ground state, thus lower IE? Coz I understand that the ionization energy refers to 0-(-energy at ground state). Thanks in advance!