Review and Discussion Questions

Author: John Hutchinson

Problem 1	The photoelectric effect demonstrates that radiation energy is quantized into "packets" or photons. Explain how and why this observation is of significance in understanding the structure of atoms.
Problem 2	Explain how we can know that higher frequency light contains higher energy photons.
Problem 3	Electron affinity is the energy released when an electron is attached to an atom. If an atom has a positive electron affinity, the added electron is attracted to the nucleus to form a stable negative ion. Why doesn't a beryllium atom have a positive electron affinity? Explain how this demonstrates that the energy of a 2s orbital is less than the energy of a 2p orbital.
Problem 4	Why does an inert gas atom have a high ionization energy but a low electron affinity? Why do these properties combine to make the atoms of inert gases unreactive?
Problem 5	Consider electrons from two different subshells in the same atom. In photoelectron spectroscopy, the lower energy electron has a higher ionization energy but is observed to have lower kinetic energy after ionization. Reconcile the lower energy with the higher ionization energy with the lower kinetic energy.
Problem 6	Chlorine atoms have 5 distinct ionization energies. Explain why. Predict the number of ionization energies for bromine atoms, and explain your answer. (Hint: examine the structure of the periodic table.)
Problem 7	Why does a Bromine atom have a much smaller radius than a potassium atom, even though a Br atom has 16 more electrons than does a K atom?
Problem 8	Explain why electrons confined to smaller orbitals are expected to have higher kinetic energies.
Problem 9	Define "shielding" in the context of electron-electron repulsion. What is the significance of shielding in determining the energy of an electron? How is the affected by core penetration?