Unit 5 Electrons Rutherford described the dense center of the atom called the nucleus But the Electrons spin around the outside of that nucleus Provide the chemical properties of the atoms Responsible for color and reactivity ID: 1031383
Download Presentation The PPT/PDF document "Electrons and Quantum Mechanics" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Electrons and Quantum MechanicsUnit 5
2. ElectronsRutherford described the dense center of the atom called the nucleus.But the Electrons spin around the outside of that nucleus.Provide the chemical properties of the atoms.Responsible for color and reactivity.
3. EnergyEnergy is transmitted from one place to another.Light carries this energy.Converted into heat.Light is called Electromagnetic Radiation.
4. Electromagnetic SpectrumRadioInfraredVisible LightROY G BIVUltravioletX RaysGamma Rays
5. LightLight travels as a wave.Wave PropertiesWavelength (λ) = distance between two waves (m)Frequency (f) = number of peaks per second (Hz)Speed of Light (c) = how fast light moves.
6. LightLight Equationc= ƒλSpeed of light is a constant = 3 x 108 m/sNothing travel faster than the speed of light!Maybe?!?!?!?!?!?!?!?!?
7. LightThe Dual Nature of LightLight carries energy through space like a wave.Light also behaves like a particle?!?A beam of light is made of tiny packets of energy called PHOTONS!Which travel in waves!?!
8. LightThe Energy of a photon depends on its frequency.So is the color of light!!!E = hƒELECTRONS are like photons!Act as waves and particles.Orbit the nucleus in a wave-like motion.
9. Blackbody RadiationRutherford could never explain why objects change colors when they are heated.As the object heats, it must give off electrons of certain frequencies and energies.
10. Photoelectric EffectSimilarly, light on a metal object can knock off electrons.Shine different colors on a metal.Measure the number of electrons knocked off.Found that no electrons were knocked off below a certain frequency.
11. The Bohr ModelProposed the electrons orbit the nucleus with fixed energies.Called Energy LevelsMuch like the rungs of a ladder.Quantum describes the amount of energy required to move an electron from one level to another.
12. The Bohr ModelGround StateLowest possible energy of an electron.Normal locationExcited StateIf electron absorbs energy, it moves up an energy level (absorption)If an electron gives off energy, it moves down an energy level (emission).
13. The Bohr Model
14. Atomic SpectraHydrogen Atom Line Emission SpectrumExpected continuous spectrum of lightBut only specific frequencies were given off.Red (656.6 nm)Blue-green (486.1 nm)Violet (434.1 nm)Violet (419.2 nm)
15. Atomic SpectraShine a light on an AtomWhen atoms absorb energy, electrons move to higher energy levels.When atoms release the energy, electrons return to the lower energy level.Atomic SpectraFrequencies of light emitted by a certain element.No two elements have the same spectrum.http://student.fizika.org/~nnctc/spectra.htm
16. Flame TestsBecause no two atoms produce the same spectrum, elements can be identified by the colors they emit.Spectral Analysis uses this properties to identify elements.
17. Quantum MechanicsMax Planck (1900)Founder of Quantum MechanicsE = hfAlbert Einstein (1905)Wave-Particle DualityElectrons are small particles that move like waves.
18. Quantum MechanicsNeils Bohr (1922)Electrons orbit in distinct energy levels.Louis de Brogelie (1923)Wave Mechanics says that ALL MATTER behaves like waves.mv/λ = h
19. Quantum MechanicsWerner Heisenberg (1927)Principle of IndeterminacyYou can’t know both the position and the velocity of an electron.Erwin Schrödinger (1930)Used wave mechanics to show the PROBABLE location of an electron.Electrons exist in 3D clouds of probability!!!
20.
21. Quantum Mechanical ModelUses Schrodinger’s equation to predict the probable location of an electron.Determines the energies an electron is allowed to have.Determines how likely it is to find the electron in various locations around the nucleus.
22. Quantum NumbersDescribes the location and behavior of an electronLike an electron’s addressNo two electrons can have the same quantum numbers.Four Numbers
23. Quantum NumbersPrinciple (1st) Quantum Number (n)The Energy LevelDescribes the size of the cloud and the distance of the cloud from the nucleus.Shows the number of electronsn = 1 = 2 electronsn = 2 = 8 e-n = 3 = 18 e-n = 4 = 32 e-
24.
25. Quantum Numbers2nd Quantum Number (l)Each energy level has sublevels.The number of sublevels equals n.Sublevels are called:s = sphericalp = peanut-shapedd = daisy-shapedf = unknown?
26.
27. Quantum Numbers3rd Quantum Number (ml)Divides sublevels into orbitals.Tells the shape the electron moves in.Number of orbitals = n2Exampless = 1 orbitalp = 3 orbitalsd = 5 orbitalsf = 7 orbitals
28. Quantum Numbers4th Quantum Number (ms)Describes the electron’s spin.Only two electrons fit in an orbital.Their charges repel causing them to spin in opposite directions (+½ or –½)Use up and down arrows.
29.
30. Quantum NumbersPauli Exclusion PrincipleNo two electrons can have the same set of 4 quantum numbers.The electrons repel each other.Hund’s RuleEvery orbital must get one electron before doubling up.
31. Quantum NumbersDiagonal RuleElectrons fill orbitals in predictable patternsSome People Do ForgetElectrons dill the lowest energy level possible.1s2s 2p3s 3p 3d4s 4p 4d 4f5s 5p 5d 5f
32. Orbital NotationDraw out the locations of each electron in an atom with arrows.
33. Electron ConfigurationWrite out the configurations of electrons using superscripts.Examples:H = 1s1He = 1s2
34. Electron ConfigurationsNoble Gas ShorthandWrite the Noble Gas just before the element.Add the remainder of the configuration.
35. Lewis Dot DiagramsA way to show the number and position of the valence electrons.Outermost energy levelLook at the column number to get this number.Use the chemical symbol and number of valence electrons.All four sides must have a dot before you double up.X p1 p3 p2 sp orbitalss orbital