The data below list the first-ionization energies for the six consecutive elements Li…
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
The data below list the first-ionization energies for the six consecutive elements Li through Ne (all values in kJ·mol⁻¹).
Li : 520 Be : 899 B : 801 C : 1086 N : 1402 O : 1314 F : 1681 Ne : 2081
Answer the following questions about how and why these energies vary across Period 2 of the periodic table.
(a) Describe the general pattern in first-ionization energy as atomic number increases from Li to Ne.
(b) Two clear deviations from the overall pattern are observed at B and at O. Identify the element immediately preceding each deviation and compare its first-ionization energy with that of the element that follows. State the numerical difference for each pair.
(c) Using principles of nuclear charge, electron shielding, and the distance between the nucleus and the electron being removed, explain the overall increase in first-ionization energy from Li to Ne.
(d) Provide a separate, detailed explanation for each of the two deviations identified in part (b). Your answer must explicitly refer to the subshell from which the electron is removed and to the relative magnitudes of effective nuclear charge (Zeff) and radius for the two elements being compared.