Which factor does NOT affect ionization energy?

Which factor does NOT affect ionization energy?

• A. Number of protons
• B. Distance from nucleus
• C. Shielding effect
• D. Number of neutrons

Answer: (D)

Ionization energy depends on how strongly the outer electrons feel the nucleus, which is governed by the nuclear charge, the distance of the electron from the nucleus, and shielding by inner electrons. More protons increase the pull on the outer electrons, closer distance strengthens that pull, and less shielding means the electrons are held more tightly, all leading to higher ionization energy. The number of neutrons does not change these electrostatic forces—neutrons are neutral and don’t contribute to shielding. So, changing the neutron count leaves ionization energy essentially the same, aside from tiny mass-related effects that aren’t considered in typical chemistry.

Ionization energy depends on how strongly the outer electrons feel the nucleus, which is governed by the nuclear charge, the distance of the electron from the nucleus, and shielding by inner electrons. More protons increase the pull on the outer electrons, closer distance strengthens that pull, and less shielding means the electrons are held more tightly, all leading to higher ionization energy. The number of neutrons does not change these electrostatic forces—neutrons are neutral and don’t contribute to shielding. So, changing the neutron count leaves ionization energy essentially the same, aside from tiny mass-related effects that aren’t considered in typical chemistry.