A research group obtained a photoelectron spectrum for an unknown noble-gas element
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
A research group obtained a photoelectron spectrum for an unknown noble-gas element. During the experiment, the detector array covering the binding-energy window from 1 000 kJ·mol⁻¹ to 800 kJ·mol⁻¹ was temporarily inoperable, resulting in partial loss of signal for one peak.
Recorded data (in order of decreasing binding energy):
• Peak A: 1 750 kJ·mol⁻¹, area ≈ 2
• Peak B: 480 kJ·mol⁻¹, area ≈ 2
• Peak C: (partially lost) center at 320 kJ·mol⁻¹, recorded area ≈ 3
No other peaks were observed above 30 kJ·mol⁻¹.
Assume that (i) the element is in its ground state, (ii) peak areas are proportional to the number of electrons, and (iii) the instrument captured roughly 50 % of the true area of Peak C because of the malfunction.
(a) Estimate the actual number of electrons that should be associated with Peak C. Show how you account for the detector loss in your calculation.
(b) Using all three peaks, determine the total number of electrons in one atom of the unknown element.
(c) Identify the element and write its complete ground-state electron configuration.
(d) Explain why no additional peaks appear at lower binding energies for this element, and relate your explanation to its position in the periodic table.