Monday, October 6, 2008
Mon-Day 1
AP Chem- we reviewed the first ionization anomalies among Group 3A elements and saw that the first IE value is LOWER than expected due to the shielding of the p electron by the two s electrons, making the p electron less attracted to the nucleus thus requiring LESS ENERGY for removal of said p electron.
We saw that Group 6A elements ALSO have anomalous/lower than expected first IE's BUT this is NOT due to s to p shielding; we drew the orbital diagrams to show that the electron pair repulsion, which is more significant between electrons in the same orbital/region of space due to their mutual proximity, causes one of those two electrons to be more easily removed from the atom.
We then explained the trend in SUCCESSIVE ionization energies to see that when the first NON-valence electron is removed, their is a DISPROPORTIONATE increase in ionization energy required. This is because NON-valence electrons are attracted to their nucleus by a much higher Zeff and these electrons are located closer to the nucleus (lower # OPEL's) than are valence electrons. Both of these factors cause greater nuclear to electron attraction.
We then defined "electron affinity" as the energy released when a gaseous atom GAINS an electron. This is measured via a laboratory procedure in which electrons are directed at a gaseous sample of atoms and the energy change is then measured. Atoms that have high EA (electron affinity) do so because of a relatively high Zeff, few OPEL's, AND not too much electron-electron repulsion as a result of gaining the new electron.
Your next test is on Wednesday and will cover all notes/subtopics done in class since the last exam (starting with Schroedinger's quantum number solutions and ending with explanations of all Periodic trends.
Bio 6/7- we continued to describe the structure and function of eukaryotic cell organelles. We saw a video comparing/contrasting eukaryotic and prokaryotic cells.
We reviewed some test questions and further discussed test-taking skills (identifying and underlining KEY TERMS in the question so that you are FOCUSED on what is actually required in your answer e.g. the pepsin PROTEIN-digesting (not starch/carb-digesting) enzyme question).
We then almost finished our Biochem lab discussion regarding pH.
Bio 8- we continued to describe the structure and function of eukaryotic cell organelles. We saw a video comparing/contrasting eukaryotic and prokaryotic cells.
We saw that Group 6A elements ALSO have anomalous/lower than expected first IE's BUT this is NOT due to s to p shielding; we drew the orbital diagrams to show that the electron pair repulsion, which is more significant between electrons in the same orbital/region of space due to their mutual proximity, causes one of those two electrons to be more easily removed from the atom.
We then explained the trend in SUCCESSIVE ionization energies to see that when the first NON-valence electron is removed, their is a DISPROPORTIONATE increase in ionization energy required. This is because NON-valence electrons are attracted to their nucleus by a much higher Zeff and these electrons are located closer to the nucleus (lower # OPEL's) than are valence electrons. Both of these factors cause greater nuclear to electron attraction.
We then defined "electron affinity" as the energy released when a gaseous atom GAINS an electron. This is measured via a laboratory procedure in which electrons are directed at a gaseous sample of atoms and the energy change is then measured. Atoms that have high EA (electron affinity) do so because of a relatively high Zeff, few OPEL's, AND not too much electron-electron repulsion as a result of gaining the new electron.
Your next test is on Wednesday and will cover all notes/subtopics done in class since the last exam (starting with Schroedinger's quantum number solutions and ending with explanations of all Periodic trends.
Bio 6/7- we continued to describe the structure and function of eukaryotic cell organelles. We saw a video comparing/contrasting eukaryotic and prokaryotic cells.
We reviewed some test questions and further discussed test-taking skills (identifying and underlining KEY TERMS in the question so that you are FOCUSED on what is actually required in your answer e.g. the pepsin PROTEIN-digesting (not starch/carb-digesting) enzyme question).
We then almost finished our Biochem lab discussion regarding pH.
Bio 8- we continued to describe the structure and function of eukaryotic cell organelles. We saw a video comparing/contrasting eukaryotic and prokaryotic cells.
# posted by C @ 4:00 PM 
