Which Statement Below Regarding Ionization Energy Is FALSE

Multiple Choice

Which statement below regarding ionization energy is FALSE?

A) Ionization energy is the energy required to remove a mole of electrons from a mole of gas-phase atoms or ions.
B) The ionization energy increases as Z_eff increases.
C) Anomalies in ionization energy trends can occur due to electron pairing in orbitals.
D) Atoms in the same column of the periodic table have equal ionization energies.
E) Ionization energies are always positive because it takes energy to pull the negative electron away from the positive nucleus.