Thursday, November 19, 2009
Fri-Day 2
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!).
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!).
# posted by C @ 11:27 PM 
