CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
Neon and fluoride ion (F⁻) are isoelectronic, yet their nuclear charges differ. A simplified PES spectrum for neon is given below. The y-axis (not shown) is photoelectron count; the x-axis increases to the right.
Neon spectrum:
• Peak A at 870 eV (height 2)
• Peak B at 48 eV (height 2)
• Peak C at 21.6 eV (height 6)
Assume identical photon energy for all measurements.
(a) Assign subshells to Peaks A, B, and C in the neon spectrum and indicate the number of electrons removed at each peak.
(b) Without collecting data, predict the relative (qualitative) binding-energy positions of the three corresponding peaks that would be observed for F⁻ under identical experimental conditions. Clearly state whether each peak would shift to higher or lower binding energy and explain why.
(c) Sketching is not required, but describe how the overall neon spectrum would differ from that of F⁻ in terms of both peak position and any differences in peak height. Account explicitly for nuclear charge and electron-electron repulsion in your explanation.
(d) Suppose a mixed gas sample containing unknown amounts of Ne and F⁻ is analyzed by PES. Propose a procedure for determining the relative molar amounts of the two species using the spectral data, and justify why your method would work.