8 1 Chapter 8 Periodic Properties of the Elements Electron Configurations Give the 4 quantum numbers and electron configuration for H He Li both electrons Be B C only the last electron added n n n n n n n l l l l l l l ml ml ml ml ml ml ml ms ms ms ms ms ms ms Three rules for determining the ground state electron configuration Aufbau procedure Pauli Exclusion Principle Hund s Rule Terms to know ground state excited state E 8 2 degenerate node shell subshell Using the periodic table to determine electron configuration Identify the s p d and f blocks Remember the s block starts with the p block starts with the d block starts with and the f block starts with Beginning with the first period proceed across the periodic table horizontally counting the electrons in the s p d and f blocks Example Write the complete electron configuration of Titanium Three other points concerning electron configurations 1 There is a special stability associated with 2 There is a special stability associated with 8 3 3 When determining the electron configuration of cations the first electrons removed are Know these terms Isolectronic Paramagnetic Diamagnetic valence electrons core electrons Example Write the complete ground state electron configuration for F F Ne Na Na Example Write the abbreviated electron configuration for V Cr Cu 8 4 Is iron paramagnetic or diamagnetic How many unpaired electrons does it have Fe 2 Fe 3 Fe Mn 2 Mn Ag Ag W Au Example Write the four quantum numbers for the last electron added in K Ga Br n n n l l l ml ml ml ms ms ms 8 5 Periodic Trends Know these terms shielding effective nuclear charge To predict periodic trends consider two things 1 2 Summary of periodic trends Atomic and ionic radii Atomic size going from left to right across the periodic table because Atomic size going down the periodic table because Ionic size 1 2 3 8 6 Example Which is bigger Na or Cl Example Which is bigger Na or Cl Ionization Energy Definition of Ionization Energy General Trend But there are important exceptions that you have to know IE1 IE2 IE3 etc IE1 Na IE2 Na Two points For a given element Notice the for Na going from IE1 to IE2 This is because IE1 Mg Which is greater IE1 Na or IE1 Mg Why 8 7 IE2 Mg Which is greater IE2 Na or IE2 Mg Why IE3 Mg Notice the for Mg going from IE2 to IE3 This is because Which is greater and why IE1 Mg IE1 Al IE1 Al IE1 Si IE1 P IE1 S Where are the exceptions Why Which is greater IE1 S IE1 Cl IE6 S IE6 Cl IE7 S IE7 Cl Problem Place in order of increasing IE1 Li Be B C N O F 8 8 Electron Affinity Definition Some electron affinities are and some are If the electron affinity is negative that means When we say that the electron affinity increases that means The trend is not as clear and there are lots of exceptions but we can say 1 Groups and have electron affinities 2 The have the most electron affinities 3 Make individual predictions based on 1 2 Which has the greater electron affinity Li or Be Which has the greater electron affinity Be or B Which has the greater electron affinity B or C Which has the greater electron affinity C or N Which has the greater electron affinity C or O Which has the greater electron affinity O or F