The photoelectron spectra above show the energy required to remove a 1selectron froma nitrogen atom and from an oxygen atom.
which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum?
a. nitrogen atoms have a half-filled psubshell.
b. there are more electron-electron repulsions in oxygen atoms than in nitrogen
c. electrons in the psubshell of oxygen atoms provide more shielding than electrons in the psubshell of nitrogen atoms.
d. nitrogen atoms have a smaller nuclear charge than oxygen atoms.

Photoelectron spectroscopy (pes) is a technique used for determining the ionization

potentials of molecules. Underneath the banner of PES are two separate techniques for

quantitative and qualitative measurements. They are ultraviolet photoeclectron

spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). UPS focuses on

ionization of valence electrons while XPS is able to go a step further and ionize core

electrons and pry them away.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.