AIIMS 2019 Chemistry Ionization Energy MCQ Question

Option D, carbon (C), exhibits the greatest difference between its first and second ionization energies due to the significant increase in effective nuclear charge experienced by the remaining electrons after the removal of the first electron. This results in a much stronger attraction to the nucleus for the second electron, leading to a higher energy requirement for its removal. In contrast, lithium (Li) and beryllium (Be) have smaller differences because their first ionization involves removing a single valence electron, while the second ionization for Li involves removing an electron from a stable noble gas configuration, and for Be, it involves removing an electron from a filled subshell, both of which require less energy compared to carbon's situation.