Lightning ReviewQuantum Number Summary28.9 The Pauli Exclusion PrincipleExamplesThe Periodic TableBit of history: Mendeleev’s original tableProblem: electron configuration of OKrypton (atomic number 36) has how many electrons in its next to outer shell (n = 3)?(a) 2(b) 4(c) 8(d) 18Characteristic X-RaysExplanation of Characteristic X-RaysMoseley PlotAtomic Transitions – Energy LevelsAtomic Transitions – Stimulated AbsorptionAtomic Transitions – Spontaneous EmissionAtomic Transitions – Stimulated EmissionPopulation InversionLasersProduction of a Laser BeamLaser Beam – He Ne Example1112/1/200312/1/2003General Physics (PHY 2140)Lecture 35Lecture 35¾ Modern Physics9Atomic Physics9The periodic table9Atomic transitionsChapter 28http://www.physics.wayne.edu/~apetrov/PHY2140/2212/1/200312/1/2003Lightning ReviewLightning ReviewLast lecture:1.1.Atomic physicsAtomic physics99De De BroglieBrogliewaves/hydrogen atomwaves/hydrogen atom99Quantum mechanics and spin2 , 1, 2,3,...rn nπλ==, 1, 2,3,...emvr n n===22111HfiRnnλ=−Quantum mechanics and spinReview Problem: An emission spectrum for hydrogen can be obtained by analyzing the light from hydrogen gas that has been heated to very high temperatures (the heating populates many of the excited states of hydrogen). An absorption spectrum can be obtained by passing light from a broadband incandescent source through hydrogen gas. If the absorption spectrum is obtained at room temperature, when all atoms are in the ground state, the absorption spectrum will1. be identical to the emission spectrum.2. contain some, but not all, of the lines appearing in the emission spectrum.3. contain all the lines seen in the emission spectrum, plus additional lines.4. look nothing like the emission spectrum.3312/1/200312/1/2003Quantum Number SummaryQuantum Number SummaryThe values of n can increase from 1The values of n can increase from 1in in integerintegerstepsstepsThe values of The values of ℓℓcan range from 0 to ncan range from 0 to n--1 in integer steps1 in integer stepsThe values of The values of mmℓℓcan range from can range from --ℓℓto to ℓℓin integer stepsin integer steps4412/1/200312/1/200328.9 The Pauli Exclusion Principle28.9 The Pauli Exclusion PrincipleRecall Bohr’s model of an atom. Why don’t all the Recall Bohr’s model of an atom. Why don’t all the electrons stay on the lowest possible orbit?electrons stay on the lowest possible orbit?Pauli’sPauli’sexclusion principle:exclusion principle:no two electrons in an atom no two electrons in an atom can ever be in the same quantum statecan ever be in the same quantum stateIn other words, no two electrons in the same atom can have In other words, no two electrons in the same atom can have exactly the same values for n, exactly the same values for n, ℓℓ, , mmℓℓ, and m, and mssThis explains the electronic structure of complex atoms This explains the electronic structure of complex atoms as a as a successionsuccessionof filled energy levels with different of filled energy levels with different quantum numbersquantum numbers5512/1/200312/1/2003ExamplesExamples1.1.Hydrogen (one electron), 1sHydrogen (one electron), 1s112.2.Helium (two electrons), 1sHelium (two electrons), 1s223.3.Lithium (three electrons), 1sLithium (three electrons), 1s222s2s11, 0, 0, 1snmm====±AA1, 0, 0, 1 21, 0, 0, 1 2ssnmmnmm====+== = =−AAAA11, 0, 0, 1 21, 0, 0, 1 22, 0, 0, 1 2sssnmmnmmnmm====+====−====±AAAAAA6612/1/200312/1/2003The Periodic TableThe Periodic TableThe outermost electrons are The outermost electrons are primarily responsible for the primarily responsible for the chemical properties of the chemical properties of the atomatomMendeleev arranged the Mendeleev arranged the elements according to their elements according to their atomic masses and chemical atomic masses and chemical similaritiessimilaritiesThe electronic configuration The electronic configuration of the elements explained by of the elements explained by quantum numbers and Pauli’s quantum numbers and Pauli’s Exclusion Principle explains Exclusion Principle explains the configurationthe configuration7712/1/200312/1/2003Bit of history: Bit of history: Mendeleev’sMendeleev’soriginal tableoriginal table8812/1/200312/1/2003Problem: electron configuration of OProblem: electron configuration of O(a) Write out the electronic configuration of the ground state (a) Write out the electronic configuration of the ground state for oxygen (for oxygen (Z Z = 8). (b) Write out values for the set of = 8). (b) Write out values for the set of quantum numbers quantum numbers nn, , ll, , mmll,,and and mmssfor each of the for each of the electrons in oxygen.electrons in oxygen.9912/1/200312/1/2003(a) Write out the electronic configuration of the ground state f(a) Write out the electronic configuration of the ground state for oxygen (or oxygen (Z Z = 8). (b) = 8). (b) Write out values for the set of quantum numbers Write out values for the set of quantum numbers nn, , ll, , mmll,,and and mmssfor each of the for each of the electrons in oxygen.electrons in oxygen.Recall that the number of electrons is the same as the charge of the nucleus. Thus, we have 8 electrons.Given:Z = 8Find:structure1, 0, 0, 1 22, 0, 0, 1 22, 1, (0, 1), 1 2sssnmmnmmnmm====±== = =±== = =±AAAAAA22 4122sspThus, electron configuration is101012/1/200312/1/2003QUICK QUIZKrypton (atomic number 36) has how many electrons in its next Krypton (atomic number 36) has how many electrons in its next to outer shell (to outer shell (n n = 3)?= 3)?(a) 2(a) 2(b) 4(b) 4(c) 8(c) 8(d) 18(d) 18(d). Krypton has a closed configuration consisting of filled (d). Krypton has a closed configuration consisting of filled nn=1, =1, nn=2, =2, and and nn=3 shells as well as filled 4=3 shells as well as filled 4s s and 4and 4p p subshellssubshells. The filled . The filled nn=3 =3 shell (the next to outer shell in Krypton) has a total of 18 eleshell (the next to outer shell in Krypton) has a total of 18 electrons, 2 ctrons, 2 in the 3in the 3s s subshellsubshell, 6 in the 3, 6 in the 3p p subshellsubshelland 10 in the 3and 10 in the 3d d subshellsubshell..111112/1/200312/1/2003Characteristic XCharacteristic X--RaysRaysWhen a metal target is When a metal target is bombarded by highbombarded by high--energy energy electrons, xelectrons, x--rays are emittedrays are emittedThe xThe x--ray spectrum typically ray spectrum typically consists of a broad