Concept:Ionization energy depends on how strongly the nucleus attracts the outermost electron.
Explanation:The size of the positive nuclear charge affects the attraction on the outermost electron.
The distance of the outermost electron from the nucleus also affects this attraction.
The screening effect of inner electrons reduces the nuclear pull felt by the outermost electron.
The ability to attract shared electrons is a measure of electronegativity, not ionization energy.
Hence, it is the factor that does not affect ionization energy.
Answer:C. ability to attract shared electron(s)