PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Ionization EnergySlide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Slide 60Slide 61Slide 62Atomic VolumeSlide 64Covalent Radii from ExperimentSlide 66Slide 67Slide 68Slide 69Bond Lengths H2 = 0.74ÅSlide 71Slide 72Slide 73Slide 74Slide 75Slide 76Chapter 17 Many-Electron Atoms and Chemical Bonding17.1 Many-Electron Atoms and the Periodic Table17.2 Experimental Measures of Orbital Energies17.3 Sizes of Atoms and Ions17.4 Properties of the Chemical Bond17.5 Ionic and Covalent Bonds17.6 Oxidation States and Chemical Bonding17.1 Many-Electron AtomsMany electron atoms and the periodic tableBuilding up electron configurationsBuilding up from H to ArBuilding from K to Kr: Transition elements and d orbitalsElectron shells and the periodic tableHund’s rule, paramagnetism and diamagnetism.1a2a3a 4a 5a 6a 7a 8 8 8 1b 2b3a 4a 5a 6a 7a8aBuilding up the table from electron configurationsElectronic structure of atoms of the elements:(1)Atoms of the various elements differ from each other in their values of Z and electrons.(2)Electrons in atoms are arranged in orbitals and shells.(3)Orbitals are characterized by the quantum numbers n, l and ml.(4)Orbitals having the same value of n are said to be in the same shell. Orbitals having the same values of n and l are said to be in the same subshell.Many electron atoms and the periodic tableComparison of the electron densities of the H atom orbitals and many electron atoms.The quantum numbers n, l and ml still have an approximate validityEvery electron in an atom has a set of four quantum numbers that describe its spatial distribution and spin state. This means that every electron in a multielectron atom occupies an atomic orbital with a characteristic size, shape, energy and spin direction.Building up electron configurationsAn electron configuration is a list of the occupied orbitals and the number of electrons in each.The electron configuration of lowest energy is termed the ground state electronic configuration.Aufbau Principle: The ground state electron configuration is built by filling the lowest energy orbitals first obeying the Pauli principle and Hund’s ruleThe orbital approximation: The electron density of an isolated many-electron atom is approximately the sum of the electron densities of each of the individual electrons taken separately.For atoms with more than one electron, approximations are required in order to make quantitative quantum mechanical approximations.The approximation amounts to treat each electron as if it were moving in a field o charge that is the net result of the nuclear attraction and the average repulsions of all the other electrons.Determining a ground state electronic configuration(1) Use the n + l rule to determine the relative energies of the atomic orbitals from 1s to …..(2) Imagine a bare nucleus of charge +Z surrounded by empty atomic orbitals.(3) Add Z electrons to the empty orbitals starting with the lowest energy orbital first, obeying the Pauli principle at all times.(4) Electrons are placed in orbitals of lowest enerEffective nuclear charge (Zeff) on the outer electronsMaintain hydrogen atom like orbitals as an approximation, but subshell energies are not equal: Ens < Enp < End < Enf A s electron penetrates to the nucleus more than a p electron: a p electron penetrates to the nucleus more than a d electron: more penetration, more stable, lower energy.Subshell energies: E3s < E3p < E3dElectron shielding of the nuclear charge by other electronsWhy is the energy of a 3s orbital lower than than of a 3p orbital? Why is the energy of a 3p orbital lower than the energy of a 3d orbital?Effective charge, Zeff, see by valence electrons**Note x-axis is incorrect. What should it be?Are the following two states allowed for N by the Pauli principle? 1s22s22px12py12pz1 or 1s22s22px22py12pz0Hund’s rule refers to the lowest energy of electron configurations allowed by the Pauli exclusions principle. It does not forbid the existence of any of the Pauli allowed configurations. If there are more than electron configurations one allowed Pauli configuration, the lower energy on will be predicted by Hund’s rule and the others will be excited states. Which is more stable?1s22s22px()2py()2pz() is more stable than 1s22s22px()2py()2pz()The presence of two orbitally and spin unpaired electrons in the ground state of carbon makes the atom paramagnetic.A paramagnetic substance is attracted to a magnetic field. A diamagnetic substance is repelled from a magnetic field. All substances which possess one or more orbitally unpaired electrons are paramagnetic.All substances which possess only spin paired electrons are diamagnetic.Paramagnetic and diamagnetic substancesExamples of diamagnetic and paramagnetic atomsWhich of the following atoms are paramagnetic?1H, 2He, 3Li, 4Be, 5B, 6C, 7N, 8O, 9F, 10Ne1H, 3L, 5B, 7N, 9F must be paramagnetic since they possess an odd number of electrons.6C and 8O are paramagnetic because of Hund’s rule:6C: 1s22s2px1py18O: 1s22s2px2py1pz12He, 4Be and 10Ne are diamagnetic.The energy of an orbital of a hydrogen atom or any one electron atom only depends on the value of nshell = all orbitals with the same value of nsubshell = all orbitals with the same value of n and lan orbital is fully defined by three quantum numbers, n, l, and mlThe energy of subshells increase with l for a given value of nThe (n + l) rule of orbital energies in a multielectron atom.Electrons fill orbitals of different energies by filling the lowest energy first. The energies of orbitals of multielectron atoms follow the (n + l) rule: the lowest value of (n + l) has the lowest energy.Examples with (n + l)1s (1 + 0) < 2s (2 + 0) < 3s (3 + 0) < 3p (3+1) ,< 4s (4 + 0) < 3d (3 + 2) < 4p (4 + 1)When n + l is the same for two orbitals, the orbital with the higher value of n has the higher energy.Shell and SubshellStructureAtomic Energy Levelsaccording to the (n + l) rule Buildup (aufbau) PrincipleRelative orbital energies for the multielectron atom.The energy of an orbital of a multielectron