SciHawks

AP Chem - we discussed second electron affinity in terms of the typical factors of attraction (Zeff, OPEL's of electrons), and repulsion (degree of electron electron repulsion in the valence shell) BUT ALSO the repulsion of the negative one charged ANION against the incoming electron.
We then related the chemical periodicity of the elements to the behavior of specific elements in single replacement redox reactions: more reactive non-metal elements gain electrons from the anions of less reactive nonmetal elements in anionic single replacements; more reactive metal elements LOSE electrons to cations of less reactive metal elements in cationic single replacements.

Bio - we showed graphically the five factors that influence the rate of photosynthesis; these factors were either the reactants (carbon dioxide, water, photons/light energy) in photosynthesis, or factors (temperature and acidity/pH) that affect the photosynthetic enzymes or chlorophyll in photosynthesis.

We then sketched a typical plant/tree to track where the ingredients/reactants in photosynthesis get into the plant/tree.

AP Chem - we applied our knowledge of the causes of successive IE's to a specific example, and predicted the group and type of compound (and formula) of an unknown element.
We then defined electronegativity, explained the trends in electronegativity across periods (left to right) and down groups, and showed its effect on element behavior and classification as metal or nonmetal.
We then defined electron affinity, and explained the few anomalies in group 2 and 15/5A.

Bio - we discussed the uses/purposes of glucose synthesis in plants and green algae.
We then discussed the various light energy absorbing/trapping pigments inside the granum in a plant cell chloroplast. We showed and explained the technique of chromatography that is used to separate the mixture of pigments that can be extracted from a plant. The greater the variety of pigment colors in a plant, the more types of colors of photons/light energy that can be absorbed, thus the more total energy for photosynthesis that can be absorbed.
We then began to discuss the factors that affect the rate of photosynthesis, and how and why they do so.

AP Chem - welcome back from Thanksgiving break! Today we reviewed the three causes of the general trend in increasing first IE across a period of elements from left to right. We then focused on the two groups of anomalies in this IE trend: group 3A and 6A. We invoked the quantum model to see that the 3A group anomaly is due to shielding of p orbital electrons by s orbital electron of the same shell. We saw that electron-electron repulsion of paired electrons in a given orbital causes the 6A group anomaly.
Of course, these anomalies could not have been predicted, but rather, we rationalize them after the fact by using the quantum atomic model.
We then discussed "consecutive" ionization energies, and saw that each successive electron requires more energy to remove; this is so firstly because each successive electron removed is from an increasingly positive cation, which naturally has an overall stronger and stronger electrostatic attraction to any electron that is being knocked out. We saw a convenient way to use this successive ionization energy data to determine the number of valence electrons in an atom of an element.

Bio - we reviewed the big picture of this unit showing the inter-relation between photosynthesis and respiration.
We then focused on the location and reactions of the two parts of photosynthesis.
In the chloroplasts of plant and green algae cells, there are stacks of thylakoids called "grana". Each granum is loaded with chlorophylls that absorb photons of light energy. This energy drives the "light-dependent" first part of photosynthesis. The light energy is converted to the chemical bond energy in ATP. Some of this energy is used to split water molecules i.e. photolysis of water molecules, to produced oxygen (which is released/diffuses out of the chloroplast and cell) and hydrogen (which gets incorporated into glucose).


We then discussed the light-independent reactions, the synthesis of glucose, which requires the ATP/energy made during the light dependent processes in the grana. The light-independent reactions occur just outside the grana, in the cytoplasm of the chloroplast called the "stroma".

AP Chem - took the unit exam on the Quantom Atom.
Look for the AP Chem Thanksgiving Assignment posted on Edline, and due on Monday.

Bio - we began our new unit: Photosynthesis and Respiration, by seeing the inter-relationship of these two processes. We defined the types of organisms that can perform photosynthesis as "autotrophs" i.e. self-nutrition suppliers, and the organisms that cannot do so as "heterotrophs" i.e. obtain nutrients by consuming other organisms.
We looked at the net chemical equation for both photosynthesis and aerobic cellular respiration, seeing that these reactions are basically the reverse of each other. In terms of energy, in photosynthesis, light energy is transformed to the chemical energy in ATP, which then provides the energy for making glucose from water and carbon dioxide. In aerobic cellular respiration, the energy stored in glucose is extracted and temporarily stored in the bonds in ATP, but ultimately the energy in ATP is released whenever the cell does any energy-requiring process.

AP Chem - I need everybody to get on board with proper test-taking skills; for six tests now, people are still not underlining/highlighting/USING keywords and data from the questions leading to a complete waste of time and effort of answering questions that do NOT EXIST. Even worse, when you rehearse a memorized answer that is not asked, you are showing a lack of effort in trying to UNDERSTAND the concept involved.
Chemistry is the most visual of all the sciences. That is why drawing what is happening in a given question must lead you to a correct or, at least, logical answer; you should start all explanations with a labeled sketch that you constantly refer to as part of your logical, detailed answer.

Today we reviewed the causes of the trend in atomic size across a period from left to right.

We then defined first ionization energy and applied the three causal factors of all periodic trends to explain the general increase in first IE from left to right across a period.
We saw that there were two anomalies in this trend per period; to explain these two anomalies, the accuracy and precision of the quantum atomic model is required.
We briefly went through the first anomaly that is explained by shielding (from nuclear charge) of p orbital electrons by s orbital electrons of the same shell/PEL.

I have posted yet another practice quantum sheet on Edline; you have an exhaustive amount of information from which you have studied for the past two weeks.
Be sure to make an effort to improve your qualitative explanations BEFORE tomorrow's exam.

Bio - took the Transcription, Translation, Mutation exam.
Multiple choice results look very good! -->  94% correct.

AP Chem - We explained in detail the periodic trend in atomic size across a period from left to right, as well as the dampening of this trend across the transition metals (left to right).
We are able to use the Bohr Model to predict the relative atomic sizes just by considering the three causal factors (introduced yesterday) and their effects.
We then explained increasing atomic size down any group.
We explained the cause and predicted the relative sizes of metal atoms and their stable cations, as well as that of nonmetal atoms and their stable anions.
We then considered the causal factors in determining the relative sizes of atoms or ions of an isoelectronic series.

Bio - we reviewed some of the hw objectives especially the meaning of the terms allele and gene. We then focused on an example of a frameshift mutation via deletion or addition.
I will post additional practice quizzes and files on Edline.

AP Chem - we began our explanation of all periodic table trends in terms of the THREE causal factors:
1. Zeff on the valence shell electrons.
2. The number of shells of electrons, i.e. electron occupied principal energy levels (OPEL's)
3. The degree of electron-electron repulsion in the valence shell of the atom.

There is a Quantum Atom unit test on TUESDAY (Day 1); be sure to do all problems posted on Edline, in order to be well prepared for this both qualitative explanation and quantitative calculation exam.
There will be a set of multiple choice questions on quantum numbers, and the various rules of electron energy order, and proper configuration in a ground state atom or ion.
The other questions cover the entire unit notes:
EMR phenomena, Planck, Einstein's explanation of the photoelectric effect
Calculation of bond energies using photons to break the bonds, or calculating the maximum wavelength of EMR that can be used to break a given bond.
the Bohr Model - both quantitative and qualitative (explanation of emission spectra)
calculation of the wavelength of a moving particle of matter using DeBroglie's equation.
the Quantum Mechanical Model of the Atom:
the Aufbau Principle, the Pauli Exclusion Principle, Hund's Rule, energy sublevel ordering,
Quantum numbers: their physical meaning and their quantitative values.
Predicting whether an atom or ion is diamagnetic or paramagnetic.
Explanations of the four anomalies to the Aufbau Principle (Cr, Mo, Cu, and Ag) in terms of energy sublevel differences and Coulomb's Law.This is a tough test for those who do not improve their explanation-writing ability. You should come to extra help with your completely written out explanations so that they may be critiqued before you lose any points on a test. Restating data, or merely describing WHAT happens is NOT an explanation; an explanation requires the logical step-by-step details of HOW and WHY something happens. For example, merely writing Planck's equation is in no way an explanation; however, using Planck's equation in explaining how the wavelength of a given EMR relates to the energy PER PHOTON is a first step of many in explaining the photoelectric effect.

Bio - we did a unit overview, and then we worked out a problem showing the transcription and translation of the normal hemoglobin allele and also of the sickle cell hemoglobin allele. We saw that a single substitution of one nucleotide of ONE codon coded for a single different amino acid in the sequence causing a drastically different-shaped sickle cell protein as compared to the normal hemoglobin protein.

AP Chem - we went through the electron configurations of elements through period 5, and explained four of the exceptions to the Aufbau Principle.
We then discussed the electron configurations of the stable ions of various elements, noting the "first in , first out" rule of losing valence electrons of transition metal atoms.
We saw the relative ease of determining the electron configurations of the (only) 11 non-metal elements that form anions.
We defined the term "isoelectronic", and then showed several isoelectronic species that make up a "series".

Bio - we discussed the regulation of genes in a cell; only certain genes are expressed, translated into the proteins that they code for, in a given cell, which causes the cell to be specialized. For example, the insulin gene is only turned "on" in certain pancreatic cells, and in no other cells in your body. We explained that it is exclusively the "environment", chemical and physical, of a cell that determines which genes are turned on or off. As a complex organism develops, different cells are in different chemical and physical environments, causing the different cells to specialize as different genes are turned on or off in the different cells.

A positive and surprisingly true story about some special people and a special horse:http://cs.bloodhorse.com/blogs/beyond-the-blinkers/archive/2011/11/15/well-armed-a-horse-with-gumption.aspx

AP Chem - we explicitly reviewed the reasons for the Aufbau Principle, Pauli's Exclusion Principle, and Hund's Rule. We then detailed the orbital diagrams and electron configurations for the elements in periods 2 and 3.
We finished with an exception to the Aufbau Principle, which we explained in terms of the miniscule 4s-3d energy difference, and the minimization of electron to electron repulsion that occurs when electrons are symmetrically distributed in a "subshell" i.e. among the degenerate orbitals of a given sublevel of energy.

In 7/8, we did the transcription-translation-protein synthesis lab- big fun!

AP Chem - we learned the relationship between pairs of quantum numbers i.e. n determines the possible l values, l determines the possible ml values.
These Schroedinger equation possible solutions to electron energies tells us physically impossible electron energies, that is, electron energies that would cause a given electron wave to interfere itself out of existence.
We listed, in order of increasing energy (sum of n+l, with a tie meaning that the lower n value is the lower sublevel of energy) the possible sublevels of energy of an electron in an atom.

We then began, element by element, using the Aufbau Principle to determine the ground state orbital diagrams and electron configurations.

AP Chem - We determined the wavelength of EMR emitted for a given electronic transition in H, and Li 2+; we saw that the greater number of protons in Li 2+ (as compared to H) causes lower PE levels of the electron in that ion yet greater energy difference for a given transition. Thus, we calculated and proved that each element emits different energy photons even for the same principal energy level transitions.
We then discussed the Schroedinger equation, which solves for the possible electron energies in a given atom by taking into account:
1. the number of protons in the nucleus
2. the wave nature of the electron
3. the particle nature of the electron
4. electron-electron repulsion in the atom
5. the angular momentum of the electron

Each solution consists of FOUR quantum numbers, the first two of which (n and l) determines the energy of the electron.
Each quantum number is associated with a physical meaning:
n- principal quantum number is associated with the average distance that the electron is from the nucleus.
l- angular momentum number tells the SHAPE of the region of probability of an electron with that specific angular momentum, l, and overall energy, n+l .
ml - magnetic spin number is associated with the orientation in space of the orbital that stems from the l number
ms - the magnetic "spin" of the electron, which is either +1/2 or -1/2 and is a magnetic property of spinning charged particles.

Bio - we did two detailed examples of transcription and translation; we learned to use the mRNA codon chart. Knowing the amino acids coded for by mRNA from this chart, we could develop a DNA codon chart or a tRNA anti-codon chart.

AP Chem - we calculated the energy if a photon emitted for a given electron transition (n=7 to n=4) in Hydrogen, and then did the same for a Li 2+ ion; we noted that, due to the greater number of protons in a nucleus of  Li 2+, the attraction of an electron to the Li2+ nucleus is greater than that of an electron towards a one proton H nucleus, thus all corresponding electron energy levels in Li 2+ are lower in potential energy AND there are different DIFFERENCES in energy between any two corresponding energy levels.
We then moved onto DeBroglie's outlandish speculation that matter could have a wave nature; we went through the derivation of the theoretical wavelength associated with a moving object. We saw that solely objects of extremely small mass (on the order of that of a proton or electron) have measureable/detectable wavelengths.
We then saw evidence of the wave nature of the electron, as discovered by G.N. Thomson, the son of the man who discovered the electron as a particle, JJ Thomson!
This wave nature discovery effectively showed a further inadequacy of the Bohr atomic model; advances in mathematics and physics led to the Quantum Model of the atom; the equations for the possible energies (energy SUBLEVELS) of an electron in any atom were developed and solved by Schroedinger.

Bio - we went , step by step, through two examples of transcription and translation, showing part of a gene/allele on a chromosome in the nucleus that ultimately led to the synthesis of the protein that it coded for, at the ribosome.

AP Chem - we discussed the Bohr model of the atom, focusing on the cause of the relative possible energies of the one electron in an H atom, He + ion , or Li 2+ ion i.e. the greater the number of protons, the greater the electrostatic attraction for the electron, thus the lower its potential energy in a given principal level. The much more important result of this is that each element has DIFFERENT DIFFERENCES in energy between any two given levels so that when an electron transition (energy level change) occurs, each different element emits or absorbs different energy photons; this is how each element has a unique emission or absorption spectrum!
Bohr's model only works for one-electron systems because it does not account for the electron to electron potential energy raising repulsion that causes different than predicted DIFFERENCES in possible energies of a given electron.
We looked at the Rydberg equation that Bohr derived from Coulomb's Law, in order to calculate the possible electron energies in a one-electron "system" i.e. atom or ion.

Bio - we reviewed the transcription/translation animation, and then we began to discuss/draw out the process of transcription.

AP Chem - we reviewed the photoelectric effect experiment, detailing the reasons that for the electron ejection rate, and the identical KE's of the ejected electrons for a given color of laser used on the sample.
We then related the quantum/particle nature of EMR to the emission spectra of atoms i.e. the spectral lines are caused by the emission of specific energy photons of the exact same energy that was lost by an electron as it lost potential (positional) energy as it got closer to the nucleus due to electrostatic attraction. Overall, the energy of an emitted photon is exactly equal to the magnitude of the energy lost by the electron; no net energy is created or destroyed.
From Coulomb's Law, Bohr calculated the possible levels of energy than an electron has depending on its distance from the nucleus; the DIFFERENCES in energy that an electron can have PERFECTLY matched the observed energies of the photons emitted from Hydrogen, or any one electron ion i.e. He + and Li 2+. However, Bohr's calculated electron energy differences did not match up with the emitted photon energies for ANY atom/element other than Hydrogen. Bohr did not account for the potential energy raising effect of electron-electron repulsion in any multi-electron atom i.e. any atom except for H.

Bio - we started our new unit on Transcription, Translation, and Genetic Mutation with an overview animation of the process of transcribing the DNA base code/sequence of a gene to an RNA base code/sequence in the nucleus (this way, the chromosomes never leave the nucleus - it would take way too much energy/ATP to transport the chromosomes every time a protein was synthesized). We then saw how the RNA base code/sequence was translated to a chain of a specific sequence of amino acids that form the specific protein that was coded for originally by the DNA gene.

AP Chem - be ready for a two to three question test covering the gas unit questions that were not covered on Monday's exam. The test will be about 20 minutes, after which we will finish the Bohr atom, and then the Quantom atom.

Bio - took the DNA, Cell Cycle, Asexual Repro exam.

AP Chem - continued learning the basis for the quantum atomic model: today we focused on Planck's particle and wave theory of light; he knew that he had to propose a quantum/particle nature of light in order to explain the "ultraviolet catastrophe" blackbody radiation curve.
His theory relating EMR's wave frequency to its energy per photon/quantum, was then supported/confirmed by Einstein's photoelectric effect experiments.
We painstakingly went through that experiment , making predictions, and seeing the empirical evidence that supported Planck's hypothesis.
We then did some quantum calculations, determining the energy per photon or per mol of photons for various forms of EMR.

AP Chem - we discussed the evolution of the progressively more accurate and precise models of the atom; better technology led to a better understanding of the evidence via more revealing data, which led to better technology, and so on.
We elaborated upon the Rutherford nuclear atomic model, and then began to discuss emission spectra in order to discuss Bohr's atomic model. We will discuss Planck's quantum theory of energy so that we can fully discuss the Bohr model of the atom and beyond.

Bio - we reviewed the types of asexual reproduction seen in various species in nature; then, we discussed methods of asexually reproducing certain plants via cutting, grafting, or layering. We saw videos of the grafting method; these videos will be available on Edline.
In 7/8, we discussed a complete scientific investigation from observations to question to hypothesis to controlled experiment to sample collected data to conclusion; we will do an example from scratch tomorrow.
We then viewed cells of rapidly dividing onion root tip cells, and of fish blastula (embryo) cells, for our mitosis/cell cycle lab.