General Chemistry Study Guide 3 Quantum Theory Wave Theory Specular Re ection if shined on a polished surface Diffuse Re ection if shined on a rougher surface Refraction change speed when moving through different media Dispersion through prism white light separates into component wavelengths Diffraction bends around edges of objects Young s Double Slit Experiment waves in phase constructively interfere waves out of phase destructively interfere Electromagnetic Radiation wave energy transmission possessing oscillating perpendicular waves electric eld vs magnetic eld travel velocity through a vacuum 2 998 x 108 m s wavelength lamda distance between two corresponding locations frequency nu cycles per second nanometers 10 9 m angstroms 10 10 m 1 Hertz Hz 1 cycles 1 second c c 2 998 x 108 m s heating results in light emission Planck s Blackbody Radiator perfect absorber emitter of radiation not all wavelengths are emitted equally intensity vs wavelength both begin at zero origin for a given T intensity reaches a maximum at some wavelength Wien Displacement Law T max c2 5 second radiation constant c2 1 44 x 10 2 K m Quanta Max Planck quantum xed bundle of energy which an atom can absorb or emit Ephoton hv hc h 6 63 x 10 34 J s Einstein s Photoelectric Effect P E electrons are not ejected from the metal plate unless a minimum threshold frequency 0 is reached work function minimum energy required to remove an electron from the metal h 0 electron volt eV 1 602 x 10 19 J kinetic energy of ejected electron EK ejected electron h Ek 1 2 mv2 Ephoton mphoton c2 Louis de Broglie h mv velocity m s mass in kg wavelength in m Bohr Emission Spectrum lines in the spectrum are electron transitions between energy levels within the atom En RH n2 absorption increasing energy levels rainbow spectrum with black bands emission decreasing energy levels black spectrum with colored bands RH 2 179 x 10 18 J Lyman UV falls to n 1 Balmer visible falls to n 2 Paschen IR falls to n 3 Rydberg Equation Echange RH 1 nf2 1 ni2 Heisenberg Uncertainty Principle uncertainty in position m uncertainty in velocity h 4pi mass in kg Schrodinger Electron Probability 2 atomic orbital represents the region in which there is a high probability of nding an electron Principal Quantum Number n energy level of orbital determines the energy of the orbital and its relative distance from the nucleus As n increases so does the energy of the orbital and its peak in the probability n 1 l 0 s n 2 l 0 s 1 p n 3 l 0 s 1 p 2 d n 4 l 0 s 1 p 2 d 3 f distribution Azimuthal Angular Momentum Quantum Number l orbital shape s sphere p dumbbell or bowtie px py pz d four leaf clover dyz dxy dx2 y2 dz2 f 7 orientations l 0 m1 0 l 1 m1 1 0 1 l 2 m1 2 1 0 1 2 l 3 m1 3 2 1 0 1 2 3 Magnetic Quantum Number m1 orbital orientation Spin Value ms direction of electron s spin each m1 holds 2 electrons with values 1 2 1 2 node point in space where the wave function has value of 0 Electron Configurations degenerate two or more entities with same energy ex 2px 2py 2pz for multi electron atoms hydrogen atom all orbitals in same energy level are degenerate not the case Aufbau Principle electrons fill orbitals from lowest to highest energy levels in electron configurations most stable electron configuration of a species is that which contains the Hund s Rule greatest number of unpaired electrons for orbitals of the same energy opposite spin electrons fill one spin direction in each orbital before pairing with the Pauli s Exclusion Principle An orbital holds max 2 electrons must have opposite spin values 1 2 1 2 Inner core electrons fill lower energy levels of atom Outer electrons fill highest energy level Valence electrons involved in forming compounds for main group outer e s for some transition metals outer e s d block e s Periodic Trends elements in increasing nuclear charge atomic Mayer based on physical properties atomic volume Mendeleev periodic law based on repeating patterns in chemical behavior via elements in increasing mass some discontinuities Mosely modern periodic law recreated Mendeleev s table by organizing electrical conductivity thermal conductivity malleability ductility luster high metallic character move down increase move right decrease melting points formation of cations nonmetallic character move down decrease move right increase formation of anions metalloids B Si Ge Ar Sb Te At exhibit both metallic and nonmetallic behavior under different conditions dull appearance low melting points poor thermal and electrical conductivity groups IA except H Alkali metals 1 IIA Alkaline earth metals 2 VIA Chalcogens 2 VIIA Halogens 1 VIII Noble Gases rarely form bonds Transition metals d block Rare earth elements f block Lanthanides row 1 Actinides row 2 ionization energy move down decrease move right increase Zeff increase energy required endothermic to remove 1 mole of e s from 1 mole of gaseous atoms high IE high work I 1312 kJ mol Zeff2 n2 effective nuclear charge Zeff Z atomic number S of shielding e s Zeff is approximation due to constantly moving electrons inner electrons shield outer electrons from pull of positive nucleus outer electrons experience net charge of nucleus and inner electrons outer electrons shield each other 2 electrons in same energy level less stable than 1 electron affinity move down less negative move right more negative many exceptions to trend the energy change that occurs upon the addition of 1 mole of e s to 1 mole of gaseous atoms or ions nonmetals large and negative formation of anion is stabilizing metals low negative or slightly positive unlikely to form anion noble gases positive or zero highly unlikely to form anion atomic radius move down increase n increase move right decrease Zeff increase positive nucleus charge protons increase therefore more pull on e cloud ionic radius follows atomic radius trend cations are smaller than parent atom due to loss of electron anions are larger than parent atom due to repulsion of an electrons Chemical Bonding electronegativity Xp ability of an atom to attract e to itself through bonds higher values represent greater ability to attract electrons greater pull high EN more negative side of polar covalent bond periodic trend move down decrease move right increase 2 Xp difference Xp values of 2 bonding atoms Xp 0 nonpolar covalent bond equally shared electrons ionic bond transfer electrons one gains one loses polar covalent bond unequally shared electrons more charge on one side