Bromine is a halogen with the ground-state electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶…
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
Bromine is a halogen with the ground-state electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁵.
A chemist wishes to predict the detailed appearance of the PES spectrum for a gaseous sample of bromine atoms and to anticipate how that spectrum would change if the atoms were converted either to Br⁻ or to Br⁺.
(a) For each occupied subshell listed in the configuration above, state the number of electrons present.
(b) Arrange all occupied subshells in order of decreasing binding energy (highest binding energy first) expected in a PES experiment, providing a brief justification for your ordering.
(c) On labeled axes, sketch a qualitative PES spectrum for neutral bromine. The horizontal axis should represent binding energy increasing to the left. Make the heights of your peaks proportional to electron count and label every peak with its subshell.
(d) Predict the specific ways in which the spectrum would change if the sample consisted of Br⁻ ions rather than neutral atoms. Address both peak heights and peak positions.
(e) Predict the specific ways in which the spectrum would change if the sample consisted of Br⁺ ions instead. Compare your predictions directly with the neutral-atom spectrum from part (c) and explain the underlying electronic reasons for each change, including shielding and penetration effects.