Cuyamaca CHEM 141 - STUDY GUIDE EXAM 3
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STUDY GUIDE EXAM 3 LIST Most of the major concepts taught for Chapters 7 8 9 and 10 Chapter 7 Electronic Structure of Atoms wavelength distance between successive peaks generally given in m cm or nm Know 1 m 109 nm Use equation c speed of light c 2 998 108 m s will be given frequency number of crests passing by a given point in 1 s given in 1 s hertz Hz wavelength distance between successive peaks generally given in m cm or nm Know 1 m 109 nm Relate energy frequency and wavelength E h hc Dual Nature of the Electron Electron can behave like a wave or a particle Planck and Quantum Theory proposed energy is absorbed and emitted as bundles quanta single bundle of energy quantum Einstein and the Photoelectric Effect Be able to describe the Photoelectric Effect Know this provided experimental evidence for light existing as particles photons Bohr Theory of the Atom ground state electron in lowest energy level excited state electron in higher energy level Electrons move in quantized orbits called energy levels around nucleus When atom absorbs energy electron jumps from lower energy to higher energy level When electron drops from a higher energy to a lower energy level it releases energy in some cases as light Know limitations of the Bohr Model Recognize energy levels further from the nucleus are closer together Calculate the E for an ni nf where ni nf electronic transition within an hydrogen atom using the Bohr atomic emission spectra equation 2 nf E 2 18 10 18 J 1 nm 1 1 097 10 2 1 1 2 nf 1 ni 2 2 1 ni Calculate the wavelength or frequency when given the energy and vice versa using the E h equation this includes knowing the definition of and the mathematical relationships between wavelength and frequency Wavelength distance between successive peaks generally given in m cm or nm Know 1 m 109 nm Frequency number of crests passing by a given point in 1 s given in 1 s hertz Hz c Discuss the failures of classical physics in explaining electronic structure and why a new model i e quantum theory was necessary to fill the gaps left by classical physics Discuss the contributions of the following scientists to the development of quantum theory quantum mechanics Planck Einstein Bohr de Broglie Heisenberg and Scrodinger This includes being able to state the success and the failure of Bohr s postulates in explaining line spectra of the hydrogen atom electronic structure Be aware of the relationships between the contributions of Planck Einstein and Bohr i e energy is absorbed or released emitted in packets called quanta Planck or photons where E photon h and this theory is seen in the photoelectric effect Einstein and that the energy of electrons are quantized and the energy of an electronic transition can be calculated using the Bohr equation Bohr and relationships for de Broglie Heisenberg and Schrodinger the electron is a standing matter wave that is not a point object but a series of points that extend into space but it is also a particle de Broglie h mv and the electron has no definite location i e x for the hydrogen electron is greater than the size of the hydrogen atom Heisenberg and that the standing matter wave can be described by a wave equation which can be solved for wave functions to give four quantum numbers Schrodinger and these quantum numbers represent the electronic address of an electron Planck and Quantum Theory Proposed energy is absorbed and emitted as bundles quanta single bundle of energy quantum Einstein and the Photoelectric Effect Be able to describe the Photoelectric Effect and calculate the threshold energy total energy kinetic energy and the velocity of the electron de Broglie Matter wave Electrons have dualistic nature sometimes behaving as particles and sometimes behaving as waves deBroglie and h mv Uncertainty principle there is a limit as to how precise we can know the position and momentum of an electron in an atom x x mv h 4 Schrodinger s wave equation can be solved to yield position probabilities and energies of electrons in atoms Give the possible values of the l and the m quantum numbers when given the value of the principal number n 1 2 3 l 0 1 n 1 ml l to 0 to l Write the values of n l and ml for each orbital in a specific p or d subshell This includes being aware of the specific characteristic of an orbital given by each quantum number i e n gives size and energy l describes the shape or type of orbital s p d f etc ml describes the orientation e g px py and pz etc and ms identifies the electron in the orbital by its spin You should also know that it requires four quantum numbers to identify an electron in an atom and that quantum numbers 1 3 i e n l and ml identify the orbital and the ms quantum number identifies the electron Know the shapes of s p d and maybe f orbitals Chapter 8 Periodic Properties of the Elements Use the periodic table to determine the number of valence electrons for main group elements This includes recognizing valence electrons are the electrons used in forming chemical bonds Recognize the correct filling order for electron in orbitals i e aufbau principle low energy to high energy Hund s rule for degenerate orbitals fill empty orbitals first and Pauli exclusion principle maximum of two electrons per orbital with opposite spins Write the condensed electron configuration for an atom e g the condensed electron configuration for Cl is Ne 3s2 3p5 Be able to draw orbital diagrams of electron configurations State the difference between the terms ground state and excited state when referring to electronic transitions in the hydrogen and multi electron atom Write electron configurations for monoatomic ions Graph explain or discuss the relationship between Zeff and atomic radius Use the periodic table to arrange a series of elements according to atomic radius ionization energy electron affinity and metallic character Use the periodic table to arrange a series of monoatomic ions according to atomic radius Graph the trend in ionization energy for elements with atomic numbers 1 54 see graph at the end of the Compare the atomic radii of atoms and their ions Calculate the Zeff for an atom where Zeff Z S Explain the difference between ionization energy and electron affinity document Explain the large increase from I1 to I2 for the alkali metals where I1 to I2 are the first and second ionization energies Chapter 9 Basic Concepts of Chemical Bonding Recognize the characteristics of or the substances containing either of the three major types of bonds

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# Cuyamaca CHEM 141 - STUDY GUIDE EXAM 3

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