CHEM1061 1st Edition Lecture 20Outline of Last Lecture I. Energy Levels in H atomsII. Ionization EnergyIII. ConversionsIV. Energy Levels in a H AtomV. AbsorbanceVI. Wave Particle DualityOutline of Current Lecture II. Compare λ of an electron and a baseballIII. Heisenberg’s Uncertainty PrincipleIV. Quantum MechanicsV. S OrbitalVI. Quantum Numbers (QNs)a. Principle Quantum Number (n)b. Angular Momentum QN (l)c. Magnetic QN (m(l))d. Spin Quantum OrbitalVII. Which sets of QN allowed?Current LectureCompare λ of an electron and a baseballMass Speed Mathematical ComputationWavelengthBaseball 142 g 25 m/s 6.626x10^-34Js/0.142kg x 25 m/s2 x 10^-34mElectron 9 x 10^-28 g 5.9 x 10^6 m/s 6.626 x 10^-34Js/9 x 10^-31 kg x 5.9 x 10^6 m/s1 x 10^-10 mThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Heisenberg’s Uncertainty PrincipleWe cannot know exactly the mass and velocity of an object without knowing its position and speed.∆X x m x ∆u >or= h/4pi∆X = uncertainty in position ∆u = uncertainty in speed Quantum MechanicsExamines wave nature of objects on atomic scale.atomic orbital: the electrons probable location Schrödinger Equation (don’t worry about these computations)(festive) H x pitchfork = E x pitchfork (psi)H= Hamiltonian Operator Pitchfork= psi = wave function (mathematical description of electrons matter wave in spaceE= energy levelsPitchfork^2 gives volumes where we are most likely to find e- (probability of finding e-)S Orbital: 90% of the time e- is in this sphereQuantum Numbers (QNs)can be either n, l, m(l), or m(s)n, l, m(l) describe the orbital whereas m(s) describes the electronPrinciple Quantum Number (n)-tells us the approximate distance of electron from the nucleus-tells us about size and energy of the atom-the larger the n value, the further the electron is from the nucleus-different n values are different shells or levels-n is always a positive integerAngular Momentum QN (l)-tells us about the shape of the orbital-area where finding the electron is most probable-called subshells/sublevels-allowed values of l depend on n (table 7.2)-values 0 (n-1) (if n=3, l=0,1,2)L value Orbital Type0 S1 P2 D3 FMagnetic QN (m(l))-orientation in space of an orbital-allowed values = -l…0…+l-number of m(l) values tell us the number of orbitals of that typeS Orbital:l=0m(l)=0P Orbital:l=1m(l)= -1,0,1Spin Quantum Orbital (m(s))-spin of electron in the orbital -allowed values = +1/2 or -1/2Which sets of QN allowed?A) N=3 l=3 m(l)=0a. NO l cannot equal 3B) N=4 l=3 m(l)=4a. NO m(l) cannot equal 4C) N=2 l=0 m(l)=0a. Yupp totally
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