Study Guide for chapter 7,8, and 9
Study Guide for chapter 7,8, and 9
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This 6 page Study Guide was uploaded by Lexie Karet on Tuesday September 29, 2015. The Study Guide belongs to at University of Denver taught by in Fall 2015. Since its upload, it has received 29 views.
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Date Created: 09/29/15
VOCAB Light Electromagnetic Radiation Wavelength The distance from crest to crest or trough Frequency of times a wave passes a point per unit Amplitude The height of the crest Wavelength Frequency C 80 x 10 8 C is a constant Refraction Bending of light waves when passing between media of different densities Diffraction as light passes through slits QUANTUM THOERY Quantized having discrete values that are restricted to Wholenumber multiples of a specific base value The energy of a quantum of radiation is Ehv Where h 6626 X 10quot 34 PHOTOELECTRIC EFFECT Illuminating metal With electromagnetic radiation releases electrons from metal surface If the electromagnetic radiation falls below a certain threshold energy no electrons are released The photoelectric effect is explained by quantum theory Photons With sufficient energy dislodge electrons from metal surfaces TYPES OF EMIISON SPECTRA Atomic Emission Spectrum consists of bright light at discrete wavelengths on a dark background Atomic absorption spectra consists of characteristics series of dark lines in a continuous spectra BOHR MODEL Electrons in H atoms 1 occupy discrete energy levels and exist only in the available energy levels 2 May move between energy levels by either absorbing or emitting energy 3 difference in energy levels shown by Delta E 2178 X 1018 1n121n22 STATES OF ELECTRONS Energy level An allowed state that an electron an occupy in an atom Ground State Lowest energy level available to an electron in an atom Excited State Any energy state above ground state PARTICLE OR WAVES De Broglie s Equation A hmu A De Broglie s wavelength m mass of electron in kg u velocity ms h Plank s constant The wave particle duality of Matter and Energy A hmu UNCERTAINTY PRINCIPLE Heisenberg Uncertainty Principle you cannot determine the position and momentum of an electron at the same time AX mAu gt h4pi WAVE EOUATIONS AND OUANTUM NUMBERS Principle quantum number 11 indicates the shell and relative size of orbital n123 Angular momentum quantum number 1 defines shape of the orbital and subshell 10 I II1 Magnetic quantum number m1 defines orbital s orientation around nucleus SHAPE AND SIZES OF ORBITALS S orbital Spherical shape with electron densities highest near nucleus P three p orbitals in each shell with ngt2 D five d orbitals in each shell with ngt3 OUANTUM NUMBER AND THE EXCLUSION PRINCIPLE Each electron in any atom is described completely by a set of four quantum numbers First 3 quantum numbers describe the orbital while the fourth quantum number describes electron spin FACTORS Energies of atomic orbital are affected by 1 nuclear charge and 2 shielding by other electrons A higher nuclear charge increases nucleus electron interactions and lowers sublevel energy Shielding by other electrons reduces the full nuclear charge to an effective nuclear charge electrons in inner energy levels shield the outer electrons very effectively Chapter 8 AUFB AU PRINCIPLE Most stable atomic structures are those in which electrons are in the lowest energy orbitals available When adding electrons to an atom 1 Electrons always go in the lowest energy orbitals available 2 Maximum of two electrons per orbital There is a single electron in H atoms that go in Is for He two electron will occupy 1s Order of configurations 1s22s22p63s23p64s2 and now for the tricky part Looking at the periodic table the transition medals are introduced These hold 10 electrons and they move back one number so after 4s2 we have 3d10 and then we continue with 4p6 Another funky part is when we get to the inner transition metals There are the f orbital and can hold 14 electrons CONDENSED CONFIGURATIONS Filled shells represented by noble gas symbol For example He Is2 represents magnesium EXCEPTION Chromium and Copper do not follow the pattern of other element Other elements in these families exhibit the same types of configurations Anomalies arise from stability association with half filled and completely filled d subshells Isoelectronic Atoms Ions Other main group elements from ions gainloss electrons needed to obtain noble gas configurations Atoms ions that have identical electron configurations are isoelectronic TRENDS Atomic Radius Increase going down a family Decrease going across a row Radius of Ions Cations loss of electrons from valence shell orbitals decrease in radius compared to atom Anions gain of electrons in valence shell orbiatls increase in radius compared to atom Ionization Energy Decrease going down a family Increase going across a row Electron Affinities EA becomes more negative moving to the right and up in the periodic table Chapter 9 TYPES OF BONDS Ionic bonding metal bond to a nonmetal Covalent bonding nonmetal to nonmetal Metallic bonding involves electron pooling and occurs when a metal bonds to another metal LEWIS THOERY Octet set of 8 electrons in valence shell Lewis electron dot symbols to draw Lewis symbol for any main group element Elemental symbol to represent nucleus and inner shell electrons Note the A group number which gives the number of valence electrons Keep adding dots till all used up Metal total number of dots in Lewis symbol is the number of electrons the atoms loses to form a cation Nonmetal the number of unpaired dots equals the number of electrons the atom gains to form an anion LATTICE ENERGY Energy required to separate 1 mol of an ionic solid into gaseous ions Lattice energy is a measure of the strength of the ionic bond Electrostatic energy charge A X charge B distance Lattice energy is affected by ionic size and ionic charge As ionic size increases lattice energy decreases Decreases down a group BONDING Shared electrons are called a shared pair or bonding pair Covalent bond bond order is the number of electrons pairs being shared by a given pair of atoms Bond energy is energy needed to overcome the attraction between the nuclei and the shared electrons The stronger the bond the higher the bond energy Bond length is the distance between the nuclei of the bonded atoms TRENDS higher bond order results in a shorter bond length and higher bond energy Bond length increases down a group and decreases across a period Bond energy shows the opposite trend POLARITY Covalent bond in which shared electron pair is not shared equally is a polar covalent bond Ability of an atom in a covalent bond to attract the shared electron pair is called its electronegativity EN ability of an atom to attract bonding electrons Electronegativity Trends increases moving up to the right Most electronegative Fluorine Decreases down a group as atomic size increases Nonmetals are more electronegative than metals
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