SciHawks

AP Chem- we explained the exceptions to the Aufbau Principle in the cases of Cr, Mo, Cu, and Ag. The explanation considers the energy-lowering effect of having 5 half-filled or fully filled d orbitals that cause the electrons to be symmetrically oriented, on average, thus causing a greater average distance between them, which lowers electron-electron repulsion. The energy required to "promote" an s valence electron to the inner d sublevel is not as much or significant compared to the energy-lowering effect of the symmetric distribution of electrons.
We reviewed Coulomb's Law and set up the THREE factors that will determine ALL chemical properties of the elements and thus chemical periodicity.

AP Chem: The take-home descriptive chemistry test is due on Monday.
As promised, I posted several Organic Chem files complete with a handy mnemonic reference file. The mnemonics file helps you to do the worksheets more easily.
You WILL see an organic combustion reaction in Part II of the AP exam, so you must be able to write/draw an organic formula/molecule from its name. Part I also has some organic molecules/formulas.

AP Chem- we did some quantum number practice and then we accounted for the relative sublevel energies of a principal energy level. We used the terms "shielding" and "penetration" to show how and why "s" electrons are lower in energy than "p", "d", and "f" electrons. Further, we saw that the more penetrating electrons shield some of the nuclear charge from the less penetrating sublevel electrons thus making those less penetrating sublevel electrons higher in potential energy; this is why, for any principal energy level with a high enough number, the relative sublevel electron energies are s < p < d < f ...

We then did some more orbital diagrams and electron configurations (these are TWO DIFFERENT terms meaning two DIFFERENT representations). Do NOT confuse these two terms or use them interchangeably!
We started to explain the Aufbau anomaly for Cr, Mo, Cu, and Ag but time did not permit a full explanation, thus this EXPLANATION will not be on the test, though you MUST know the four anomalous elements' electron configurations and orbital diagrams.

Bio 3/6- took the unit exam on transcription, translation (protein synthesis), and mutation.

AP Chem- we discussed the inability of the Bohr Atomic Model to account for many of the emission lines in all elements except Hydrogen. We then looked at the basis of the Quantum Mechanical Model of the atom, which treat the electron as a particle and a wave and accounts of electron-electron repulsions.
The Schroedinger equation solves for the "allowed" energies of all electrons in an atom.
Each electron's energy and approximate region is described by four quantum numbers: n, l, m(l), and m(s).
We then saw that the principal quantum number limited the angular momentum/azimuthal quantum number to a certain range of values. We also saw that the azimuthal quantum number determines the possible number of orientations that the orbitals can have in space. Magnetic spin number can be only one of two values: + 1/2 and -1/2.
We then applied this new information to earlier orbital language i.e. s, p, d, and f sublevels are associated with the azimuthal quantum numbers 0, 1, 2, and 3, respectively.
we made good strides today in understanding the real HOW and WHY of atomic electronic structure. No longer will we just say,"two electrons per orbital" or "2s is lower in energy than 2p" but we can now explain WHY these facts are so. As promised, everything has to do with degrees of attraction and repulsion (and wave INTERFERENCE!), though we now use "fancier" words like "shielding" and "penetration".

We saw the Aufbau Principle in practice as we assembled the ground state ORBITAL DIAGRAMS ("the boxes with the arrows") and ELECTRON CONFIGURATIONS (just principal quantum number with the sublevel "letter" and the total number of electrons in each energy sublevel) for each of the elements. On Monday, we will see and EXPLAIN two important exceptions to the Aufbau Principle. In assembling the orbital diagrams, we looked to experimental evidence and logical explanations involving electron-electron repulsion to come up with the Pauli Exclusion Principle (two OPPOSITE spin electrons MAXIMUM per ORBITAL=single region of space also known as "no two electrons in an atom can have the SAME FOUR quantum numbers") and Hund's Rule (maximize parallel spins of electrons in degenerate orbitals!).

Bio 3/6- we reviewed for the unit exam by completing our transcription, translation, and mutation exercise with the gene for normal and sickle-cell hemoglobin.
We reviewed the video that we saw at the beginning of the unit, now that we know each of the processes in detail.
We begin the second quarter KNOWING how crucial test-taking skills are in preventing careless errors and in confidently dealing with questions on any exam. Practice and employ these skills on tomorrow's exam: IDENTIFY keywords in each question (ANY answer that does not INCLUDE/ADDRESS the keywords is AUTOMATICALLY wrong on ANY exam!); PREDICT an answer based on your knowledge/pre-drawn LEGAL cheatsheet (information that you KNOW will be tested but are afraid that you might forget during the test). If your prediction is not found, ELIMINATE answers that are not possibly correct and guess among the remaining choices.


AP Chem- we discussed the solutions to the Schroedinger equation, which takes into account the wave and particle nature of the electron as well as all proton to electron attractions and electron to electron repulsions in ANY atom or ion!
The solved equation yields FOUR quantum numbers that indicated the energy (and APPROXIMATE LOCATION, most of the time) of an electron in an element.

Bio 3/6- we began our unit review with fill-in and illustration quiz regarding the process of protein synthesis via transcription of DNA to mRNA and translation of the coded information in mRNA to a protein. We saw that a single gene/allele codes for the synthesis of a single specific (unique shape and function) protein/polypeptide.
We then discussed gene regulation/control by the environment: many physical and chemical factors determine whether a gene is turned "on" or "off". When a gene is turned "off" in a cell, the protein that is coded for does NOT get synthesized and so the trait caused by that protein is not seen/expressed.
Different cells in a multi-cellular organism have different genes turned on or off even though these different cells have identical DNA/pairs of chromosomes.

AP Chem- we discussed the most unintuitive and radical "outside the box" thinking (AFTER DeBroglie had mastered EVERYTHING that was "inside the box"!!!) by Louis DeBroglie, who calculated the theoretical wavelength of a moving object/piece of matter. His conjecture was later supported by the most astonishing thing ever seen in the history of "particle" physics- an interference pattern caused by ELECTRONS! For the first time, the wave nature of matter (electrons) was observed as they exhibited a wave interference pattern. GN Thomson, the son of the original discoverer of the electron, JJ Thomson, discovered the electron as a wave!

We calculated the wavelength of a moving baseball and of a faster moving electron. Only objects that have ultra-light masses have wavelengths that are practically measurable by any instrument.
We then introduced the quantum atomic model that takes into account the wave nature of the electron.

Bio 3/6- we discussed gene regulation, that is the influence of the environment on genetic "expression". A trait that is coded for by a gene will not be expressed/be seen if the gene is "turned off" due to particular environmental factors i.e. temperature, light intensity, glucose level, pH, etc.

We also defined the term allele, which is the same as a gene but is just a more specific term. An allele is a specific version of a given gene i.e. the gene for blood type has at least three different alleles: A, B, and O. The gene for the number of digits on your hand has the five-finger allele and the six-finger allele.

We then did a transcription and transcription activity that compares the hemoglobin made from the normal gene and the sickle cell gene.

AP Chem- we further discussed the Bohr model of the atom, explaining the meaning/factors influencing the principal energy level of an electron equation. We explained how the bright line emission spectrum is formed.
We reviewed the meaning of the wave and particle nature of light and drew pictures associated with each term.
We then expanded Bohr's equation for any one electron element (typically ions) and explained why Bohr's model fails for multi-electron systems.

Bio 3/6- we did explicit examples of addition/insertion and deletion mutations. We saw how and why these mutations are called "frameshift" mutations; we first used an analogy to show how a shift in just one letter of a sentence that is read three letters at a time can drastically change the meaning of the sentence just as a shift in just one nucleotide of a gene can drastically change the amino acid sequence that is coded for!
We then did a review worksheet, the answers to which are posted on Blackboard.

AP Chem- we did bond dissociation energy calculations by using the minimum energy per photon required to break a covalent bond in a molecule. Most of these calculations involve an initial conversion from energy required to break one MOLE of bonds to the energy required to break literally ONE bond; we do this because ONE photon is required to break (knock out the electron from between the two nuclei) ONE bond.
We then explained Bohr's interpretation of the emission spectrum of (excited) Hydrogen atoms.
We used this explanation to draw the SPECIFIC allowed energies (and energy transitions) in any hydrogen atom: We took Planck's relationship between the wavelength of electromagnetic radiation and its energy per photon and related that to the light emission spectrum for hydrogen. Bohr developed his model of the atom based on this experimental evidence that proved that electrons could only have certain specific quantities of energy (their "energy levels"). When an electron either absorbs/gains or emits/loses energy, the energy absorbed or emitted MUST BE exactly equal to the energy difference between the "energy levels" through which the electron underwent a TRANSITION. So electrons in hydrogen atoms can only absorb or emit specific energy photons, which is why the emission spectra is not a continuous rainbow of every possible energy photon.The bright lines seen on an emission spectrum MUST be the result of specific energy photons that were emitted due to the electrons in the atoms losing energy as they underwent transitions between two specific energy levels. The larger the energy level transition, the larger the energy of photon emitted.Bohr, using certain physical laws/equations, developed an equation to predict the exact energy levels that exist/are allowed in a hydrogen atom. We used this equation to calculate some possible energy level differences (e.g. n = 6 to n = 3 electron transition) so that we could predict what energy/"color" photons could be emitted and seen on the emission spectrum film.

Bio 3/6- we discussed and drew examples of the various types of point mutations as well as the types of large-scale chromosomal mutations.
We showed how a substitution mutation could result in an altered/mutated sequence of amino acids thus forming a different, usually non-functional, protein.
We then did a lab activity simulation of transcription and translation.

AP Chem- we did some Planck equation calculations for various frequencies and wavelengths of EMR/light.
We then slowly and painstakingly spent almost the entire period explaining the photoelectric effect, which is crucial in understanding the particle nature of light. This knowledge is required in order to begin to understand Bohr's Model of the atom.

The 1st quarter multiple choice bonus exam (only available this quarter) will be given Monday after school. There is no makeup, due to the logistics and security of the exam. Your score cannot negatively affect your quarterly average but, if you score higher than your current average, your grade will be averaged in to your quarterly grade- there is no grade replacement.

As always, there is extra help in Room 308 on Monday morning. Will nobody be there again?

Bio 3/6- we viewed and discussed the various types of genetic"point" mutations, a single nucleotide change/mutation/alteration in the sequence of DNA nucleotides that make up a DNA molecule/chromosome.
The three types of point mutations are named logically:
substitution- one nucleotide replaces/substitutes for another in the sequence
addition- one extra/additional nucleotide is added somewhere in the nucleotide sequence
deletion- one nucleotide is removed/deleted from somewhere in the nucleotide sequence.

These changes/mutations cause a difference the sequence of amino acids that are coded for by the DNA/gene thus forming a protein with a different shape and function (usually the mutant protein is non-functional); there is a possibility of a "silent mutation" in which a DNA triplet is changed but still codes for the same (redundant) amino acid.

AP Chem- we discussed the major models of the atom that evolved as knowledge and technology developed and provided more accurate and precise empirical evidence.
We then discussed Planck's explanation of "blackbody radiation" and showed the implications of his conclusion that energy itself exists in little packets called quanta (photons). We did calculations with Planck's equation showing the energy per photon of a given color of light/type of EMR based on either frequency or wavelength.

Bio 3/6- we got into the heart of this unit on transcription and translation by starting with a "gene" on a chromosome in the nucleus; the sequence of bases that make up the gene were transcribed to make an mRNA molecule with the same coded information. We then transported the messenger RNA to the ribosome where each mRNA codon (a "triplet" of three bases) attracted a complementary tRNA "anticodon" that brings along a specific amino acid to be bonded to part of a protein chain of amino acids.
We saw that we could use an mRNA codon chart to see which particular amino acid is coded for/called for at the ribosome by each codon of an mRNA molecule. Using our known rules of complementary base pairing between RNA and DNA, we were able to assemble a DNA "codon" chart. We could also assemble a tRNA codon chart. Any of those three charts/ciphers/keys could be used to predict the sequence of amino acids that make up a given protein based on the DNA "gene", its mRNA transcript, or even the sequence of tRNA anticodons that are attracted to the mRNA on the ribosome.
We then showed that the protein formed (usually an enzyme or some structural protein) gives the cell one of its characteristics/traits or gives the organism itself a particular trait/characteristic.

AP Chem- Your grades are now linked via Blackboard, though the summer assignment grade has not yet been posted. Your username is your last name and your password is the first letter (lowercase; not capitalized) of your last name followed by your student ID number (no spaces).
For a couple of students, one or two grades might be missing. If that is the case for you, email me and bring in the tests/lab/hw that is missing, thank you.
The one and only quarterly bonus multiple choice exam will be given Monday after school in Room 308.

We began our Quantum Atom unit with a discussion of electromagnetic radiation and the characteristics of waves.
Go to Blackboard and view the tutorials posted as well as the study guide.
I also posted the objectives that will be tested on the "bonus" exam.

BIG, beautiful Zenyatta easily runs by and dwarves the world's best colts and geldings to become the first mare ever to win the BC Classic. Her unique combination of genes from her sire and dam (dad and mom) gave her the potential (via transcription and translation of those genes) for her enormous size, her great speed, and her special personality.

Bio 3/6- we began our unit on Transcription, Translation, and Genetic Mutations with an overview of those processes. We watched an animation (posted on Blackboard) of DNA transcription to mRNA, followed by the translation of the mRNA to a protein. We noted the structures, their functions, and the locations of the processes.
All of the characteristics of an organisms are due to proteins, especially enzymes, which control the synthesis of proteins and ALL other biological molecules. These proteins are specified, coded for, by DNA, a nucleic acid that makes up your chromosomes. DNA cannot directly give an organism its traits because DNA has the consistency of spaghetti/long-thin pasta. However, because DNA has a complementary base pairing structure, and consists of long sequences of up to four different nucleotides/nitrogenous bases, DNA can CODE FOR the building/assembly/synthesis of a particular sequence of amino acids i.e. proteins that can directly cause/influence metabolic reaction and also physically make up an organism!

Understanding this central dogma of molecular biology at the molecular level enables scientists to truly control "nature"/organisms and fundamentally can change (benefit or harm) how humans manipulate their environment.

AP Chem- we discussed bond enthalpies/bond dissociation energies and showed how they can be used to calculate the change in enthalpy/potential energy for a chemical reaction.

Bio 3/6- took our DNA/Cell Cycle/Asexual Reproduction exam today.

AP Chem- we did a Hess Law problem in which we used the longer, algebraic process of flipping or multiplying (or both) a series of reactions and their respective changes in enthalpy to get an overall net reaction with a net enthalpy change.
We then did a Hess problem using heats of formation of aqueous ions to determine the heat of reaction for a single replacement of iodide by bromine.
We then continued our redox titration lab, getting closer/refining our procedure so that we can get accurate titration data.

Bio 3/6- remember, pre-test extra help in Room 301 at 8:15 AM on Thursday!! Be there, Mahalo!

We reviewed for tomorrow's exam by going over the more difficult objectives and then we discussed our last two labs.

AP Chem - will post the notes when my computer battery recharges.
We did a couple of the longer version algebraic Hess Law problems; we then contrasted the calorimetric data from bomb and coffee cup calorimeters and related the data to the first law of thermo.
We showed how to get the value of work even when the change in volume data is not given; we just use the ideal gas law equation instead.

Bio 3/6- we reviewed the types of vegetative propagation (asexual reproduction for plants) with specific examples. I will post (on Blackboard) the answer keys from today's Cell Cycle and DNA Replication handouts.

AP Chem- just posted two Thermochem practice exams with detailed answer keys. You already have a copy of the questions from one of these two practice tests but now you can check your answers with my key. I'll also post other relevant practice files.
Today, we reviewed the Hess Law problem from Friday, emphasizing the importance of ESTIMATING your answer BEFORE you do all of the calculator key punching. Do NOT shortcut this process; many have done so and paid the penalty for such laziness and hubris.

We then did a, from scratch, combined calorimetry and Hess Law problem. This problem showed that the enthalpy data does not pop out of nowhere; the data comes from real experimental measurements via calorimetry.
We still have some objectives to cover but you should make a big dent in your preparation for Monday's exam.