MDCAT Chemistry MCQ #807

Why does the first ionization energy of aluminum fall below that of magnesium?

MDCAT Chemistry MCQ #807

  1. Question 1

    Q1. Why does the first ionization energy of aluminum fall below that of magnesium?

    • A) Lower effective nuclear charge
    • B) Shielding by d-electrons
    • C) Electron removed from p-orbital
    • D) Greater atomic radius

    Answer: Electron removed from p-orbital

    Explanation: Al's 3p electron is easier to remove than Mg's 3s. Option B is irrelevant as no d-electrons are involved.