Lecture 3-4 January 25/27, 2016Gouy Balance for Magnetic SusceptibilitySlide Number 3Electron Assignments: Identifying each and every quantum number for each and every electron: n l ml ms Electrons Characterized bySlide Number 6Figure 1.4 The possible sets of quantum numbers for n = 1 and n = 2. Figure 1.5 The possible sets of quantum numbers for n = 3.Ground State vs. Excited State ConfigurationsTerm Symbols for Ground State Electronic ConfigurationsRussell Saunders Coupling (L-S Coupling) for Ground StatesRussell Saunders Coupling: Spin/Orbit CouplingSlide Number 13Trends in Atomic PropertiesSlide Number 15Slide Number 16Slide Number 17Slide Number 18Trends in Atomic PropertiesSlide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Electronegativity-Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Lecture 3-4 January 25/27, 2016 Electrons in Atoms: Magnetism; Term Symbols, Zeff, and Other PropertiesGouy Balance for Magnetic SusceptibilityThree types of Magnetic Behavior Paramagnetism: atoms, molecules, and solids with unpaired electrons are attracted in a magnetic field—Decreases with increasing T. Diamagnetic: substances with no unpaired electrons which are weakly repelled in a magnetic field—no dependence on T. Ferro-magnetism: the unpaired electons are aligned with their neighbors even in the absence of a magnetic field Magnetic domains: the groups of mutually aligned spins in a ferromagnetic substance Ferro-magnet In the absence of a magnetic field Ferro-magnet In the presence of a magnetic fieldElectron Assignments: Identifying each and every quantum number for each and every electron: n l ml ms How do we approach magnetism?Electrons Characterized by a) Principal energy level, n b) Orbital or angular momentum, l = # of angular nodes c) Zeff -----------------------------------------------------------In the presence of a magnetic field of l is oriented and composed of ml components. d) Spin-spin and spin-orbital couplingFigure 1.4 The possible sets of quantum numbers for n = 1 and n = 2. Box Diagrams ml valuesFigure 1.5 The possible sets of quantum numbers for n = 3. Box Diagrams ml valuesGround State vs. Excited State Configurations Spin: S = Σ ms = total spin angular momentum 2S + 1 (called spin “multiplicity”) L = total orbital angular momentum Term Symbols: 2S + 1 LJ J = L + STerm Symbols for Ground State Electronic Configurations • Pauli Exclusion Principle => Assignments to n and to l quantum numbers. But there are other possibilities within assignment • Hund’s Rule: Describes ground state only. • Ground states will have 1st * Maximum value of S 2nd * Maximum value of L within that SRussell Saunders Coupling (L-S Coupling) for Ground States Configuration => Term Symbol ΣmL = max. ML or L ΣmS = MS or S 2 S + 1 J ≈ 2 S + 1 # unpaired e- S 2 S + 1 L State 1 1/2 2 ⇒ doublet 0 ⇒ S 2 1 3 ⇒ triplet 1 ⇒ P 3 3/2 4 ⇒ quartet 2 ⇒ D 4 2 5 ⇒ pentet 3 ⇒ F 4 etc. ⇒ G Spin MultiplicityRussell Saunders Coupling: Spin/Orbit CouplingInorganic Chemistry Chapter 1: Figure 1.22 © 2009 W.H. FreemanTrends in Atomic Properties • Size (atomic, ionic, covalent, van der Waals radii) • Ionization Potential (A0(g) + I.E. A+ + e- ) • Electron Affinity Energies (A0(g) + e- A- + E.A.E.) • Electronegativity: Ability of an atom, within a molecule to attract electrons to itself.Inorganic Chemistry Chapter 1: Figure 1.23 © 2009 W.H. FreemanInorganic Chemistry Chapter 1: Table 1.3 © 2009 W.H. FreemanInorganic Chemistry Chapter 1: Figure 1.24 © 2009 W.H. FreemanInorganic Chemistry Chapter 1: Table 1.4 © 2009 W.H. Freeman Anions are Larger than Neutral atom Cations are smaller than Neutral atomTrends in Atomic Properties • Size (atomic, ionic, covalent, van der Waals radii) • Ionization Potential energy (A0(g) + I.E. A+ + e- ) • Electron Affinity Energy (A0(g) + e- A- + E.A.E.) • Electronegativity: Ability of an atom, within a molecule to attract electrons to itself.Inorganic Chemistry Chapter 1: Figure 1.25 © 2009 W.H. FreemanCopyright © 2014 Pearson Education, Inc.Inorganic Chemistry Chapter 1: Table 1.5 © 2009 W.H. FreemanInorganic Chemistry Chapter 1: Table 1.6 © 2009 W.H. FreemanBDE: 427 436 kJ/molElectronegativity- • Pauling • Mulliken • RochowBDE H2 = 436 kJ/mol BDE Cl2 = 239 BDE HCl = 427 Pauling: If strictly covalent: BDE HCl should be average of H2 and Cl2 Which would be ½ (436 + 239) = 338 kJ/mol. The extra stability is Due to electronegativity difference, and electrostatic attraction. Linus PaulingInorganic Chemistry Chapter 1: Figure 1.27 © 2009 W.H. FreemanInorganic Chemistry Chapter 1: Figure 1.28 © 2009 W.H.