Question

The photoelectron spectra of the [2p] electrons of [cen] and [ces] are shown below. A photoelectron spectrum shows two peaks with the following binding energies and intensities. Peak 1 (labeled peak s): 9 mJ/mol, 6 units. Peak 2 (labeled peak n): 3 mJ/mol, 3 units. Which of the following best explains the difference in signal intensity for the two peaks?

1) The [cen] molecule has a higher electron affinity than the [ces] molecule.
2) The [cen] molecule has a lower ionization energy than the [ces] molecule.
3) The [cen] molecule has a higher ionization energy than the [ces] molecule.
4) The [cen] molecule has a lower electron affinity than the [ces] molecule.

Answer 1

The difference in signal intensity for the two peaks can be explained by the ionization energies of the molecules. The [cen] molecule has a lower ionization energy than the [ces] molecule.

Step-by-step explanation:

The difference in signal intensity for the two peaks in the photoelectron spectra can be explained by comparing the ionization energies and electron affinities of the [cen] and [ces] molecules. The binding energy of an electron in a molecule is related to the ionization energy, which is the energy required to remove an electron from an atom or molecule. A lower ionization energy means it is easier to remove an electron and therefore will result in a higher signal intensity.

In this case, peak 1 (peak s) has a higher binding energy and intensity, indicating that the [cen] molecule has a lower ionization energy compared to the [ces] molecule. Therefore, option 2) The [cen] molecule has a lower ionization energy than the [ces] molecule best explains the difference in signal intensity between the two peaks.