Chemblog!

AP: today we covered the rules and EXCEPTIONS to the Aufbau Principle. We went through the electron configuration of the 4th Period elements and detailed why Cr and Cu do not exactly follow the Aufbau Principle. We also covered diamagnetic and paramagnetic atoms as related to orbital diagrams and electron configurations. All odd-atomic number atoms are paramagnetic because they MUST have at least one unpaired electron; SOME even-atomic number atoms are paramagnetic depending on whether or not they have at least one unpaired electron.
These orbital diagrams will be used to thoroughly explain the "periodicity" of the Periodic Table.

D/G:today we covered the EXCEPTIONS to the Aufbau Principle. We went through the electron configuration of the 4th Period elements and detailed why Cr and Cu do not exactly follow the Aufbau Principle. We discussed electron-electron repulsion and its effect on the potential energy of the electrons in the atom. We discussed "symmetric distribution of negatively charged electrons" (which results when a given SUBLEVEL is half-filled or fully filled) and how the symmetric arrangement causes the electrons to be, on average, FARther apart; this results in less OVERALL electron-electron repulsion which lowers their OVERALL potential energy.

E: we reviewed some of the properties of the elements and listened to the circus that was going on in the courtyard. We began to explain the SIX super-important trends across the periods and down the groups/families of the periodic table. These trends are outlined in the notes BUT make sure that you take very good notes on these explanations next week. We should cover enough ground to have a test or at least a quiz (shorter time for a quiz) on next Thursday.