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Electron Properties and Arrangement Chapter 5

Electron Properties and Arrangement Chapter 5. Objectives: Identify and connect the properties of light with electrons. Observe how electrons move in atoms. Investigate how the quantity and organization of electrons can distinguish atoms from one another. Electrons in Atoms.

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Electron Properties and Arrangement Chapter 5

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  1. Electron Properties and ArrangementChapter 5 Objectives: • Identify and connect the properties of light with electrons. • Observe how electrons move in atoms. • Investigate how the quantity and organization of electrons can distinguish atoms from one another.

  2. Electrons in Atoms What do you know about electrons in atoms?

  3. Electrons and Light Particles Similarities: • Very tiny particles • Extremely small masses • Move at very high speeds (3.0x108 m/s)

  4. Wave-Like Properties • Crest = • Trough= • Wavelength = • Amplitude=

  5. Wave-Like Properties Frequency (υ) :

  6. Electromagnetic Radiation Spectrum • Electromagnetic Spectrum : Divides light particles into regions based on their wave-like properties. • a. Relationship b/w wavelength and frequency? • Relationship b/w wavelength and energy emission? • Relationship b/w frequency and energy emission?

  7. Electromagnetic Spectrum Applications • Wavelength and Frequency are indirectly related to one another. λ = c/υλ = wavelength (metric units) c = speed of light (3.0x108m/s) υ = frequency (Hz or 1/s) • Energy and Frequency are directly related to one another. E= hυ E = energy emitted (Joules) h= Plank’s constant (6.6 x 10-34Js) υ = frequency (Hz or 1/s)

  8. Electromagnetic Spectrum Calculations a. Calculate the wavelength of a yellow light emitted by the sodium lamp if the frequency of the yellow light is 5.10x1014 Hz. (λ = c/v) b. Using data from above, calculate how much energy the yellow light is radiating. (E= hv)

  9. Bell Ringer 10/18/11 • An Iodine atom has 54 electrons. • Is it a cation, anion, or neutral atom? • Express its symbol with correct charge if applies. • A Manganese atom has 23 electrons. • It is a cation, anion, or neutral atom? • Express its symbol with correct charge if applies. 3. Draw a wave and label its crest, trough, amplitude and wavelength.

  10. Bell Ringer 10/18/11 • An Iodine atom has 54 electrons. • Is it a cation, anion, or neutral atom? • Express its symbol with correct charge if applies. • A Manganese atom has 23 electrons. • It is a cation, anion, or neutral atom? • Express its symbol with correct charge if applies. • a. Draw a wave and label its crest, trough, amplitude, and wavelength. b. Draw another wave that exhibits a higher frequency.

  11. Electromagnetic Radiation Spectrum • Electromagnetic Spectrum : Divides light particles into regions based on their wave-like properties. • a. Relationship b/w wavelength and frequency? • Relationship b/w wavelength and energy emission? • Relationship b/w frequency and energy emission?

  12. Electromagnetic Spectrum Applications • “Electromagnetic Spectrum Song” by Emerson and Wong Yann

  13. Continuous Spectrum Continuous Spectrum = Presence of all light particles in the visible region.

  14. Absorption Spectrum Absorption Spectrum = Presence of dark bands that indicate light particles absorbed by matter. • At room temperature we observe light particles reflected.by matter.

  15. Visible Spectrum Lab • Predict and observe the absorption spectrums of several samples of matter.

  16. Atoms Interaction with Light Particles Light Particles Atom Electrons absorb light particles • Electrons absorb specific light particles or photons. • Photons = light particles identified by energy they give off • Electrons that absorb photons move to higher energy levels.

  17. Bohr’s Model of the Atom The electron cloud consists of energy levels. Electrons reside and move around in these energy levels. Electrons can move to other energy levels when absorb photons.

  18. Electron Movement 1. 2. 3. • Ground state of H Atom (lowest energy level for e-) • A photon (light particle) is absorbed by H’s electron. • Electron becomes excited and jumps to higher energy level. • 3. E- returns to ground state and emits (releases) the photon. • Emitted photon’s wavelength can be detected by scientists. • (Infrared region at room temp; Visble region at higher temps.)

  19. Bell Ringer: Electron Movement • What are photons? • What are energy levels? • Explain the movement of electrons in an atom using the following terms: (photons, absorption, emission, energy levels, ground state, and excited state)

  20. Flame Test Lab Purpose: • Heat matter (atoms) so that we can observe the emission of photons from electrons. Conclusions: • Electron movement occurs instantaneously. • Elements’ electrons emit off different photons of energy and color. • Identify elements by the distinct color (photons) they emit off.

  21. Continuous Spectrum Review Continuous Spectrum = Reflection of all light particles by electrons in the visible region. Ex. sun; white light bulbs

  22. Visible Region Absorption Spectrum Absorption Spectrum =Reveals what light particles are reflected and absorbed by electrons.

  23. Electron Movement 1. 2. 3. • Ground state of H Atom (lowest energy level for e-) • A photon (light particle) is absorbed by H’s electron. • Electron becomes excited and jumps to higher energy level. • 3. E- returns to ground state and emits (releases) the photon. • Emitted photon’s wavelength can be detected by scientists. • (Infrared region at room temp; Visble region at higher temps.)

  24. Emission Spectrum Emission Spectrum =Reveals what photons are emitted during electron movement. Ex. Hydrogen Light chemed.chem.purdue.edu

  25. Emission Spectrums • Emission spectrum for each element is unique.

  26. Bell Ringer 1. What is an emission spectrum? 2. Why can scientists identify elements by their emission spectrums? 3. Determine if a purple photon or red photon emits more energy?

  27. Emission Spectrum Emission Spectrum =Reveals what photons are emitted during electron movement. Ex. Hydrogen Light chemed.chem.purdue.edu

  28. Each photon emitted determines what energy levels the electron is moving between. • -For electron movement to occur, electrons must absorb or emit a specific quantum of energy. • Quantum of energy: Energy difference between energy levels. Electron Movement in Energy Levels

  29. Electromagnetic Radiation Spectrum • Electromagnetic Spectrum : Divides light particles into regions based on their wave-like properties. • a. Relationship b/w wavelength and frequency? • Relationship b/w wavelength and energy emission? • Relationship b/w frequency and energy emission?

  30. Each energy level has an energy value. • Quantum of energy: Energy difference between energy levels. • -For electron movement to occur, electrons must absorb or emit a specific quantum of energy. Electron Movement in Energy Levels

  31. Emission Spectrums • Emission spectrum for each element is unique.

  32. Locating an Electron Is it possible to know the position and velocity of an electron at any time?

  33. Locating an Electron Is it possible to know the exact location and velocity of an electron at any instant in time? Very difficult to locate an electron because: - moving extremely fast -continuously bombarded by light particles When locate an electron with a photon from a microscope, it changes its velocity in unpredictable ways.

  34. Heisenberg Uncertainty Principle After Before Photon changes wavelength Photon It is not possible to know the exact position and velocity of an electron at the same time.

  35. The Quantum Atomic Model • An atomic model that best explains the probablemovement and arrangement of electrons at any moment in time. • Schrodinger proved this model using a complex mathematical equation. • Depends upon 4 quantum numbers. Erwin Schrodinger

  36. n-Quantum Number n = energy levels • 3-D region of space around the nucleus where an electron can be found. • Each energy level has a specific energy value. • E- must absorb or release a specific quantum of energy to move between energy levels. • E- do not travel in the same path or shape around the nucleus. Atomic orbital:Probable paths an electron could take around the nucleus.

  37. n-Quantum Number n = energy levels ? • E- do not travel in the same path or shape around the nucleus. Atomic orbital:Probable paths an electron could take around the nucleus.

  38. Energy Levels and the Periodic TableAssociate energy levels with rows on periodic table.

  39. n-Quantum Number n = energy levels • Limited number of electrons on each energy level. (2n2 Rule ) What is the maximum number of electrons on each energy level below: 2n2 n=1 : n=3 :

  40. l –Quantum Number l-number : • Sublevels within an energy level. • Sublevels identify the shape of the orbitals (paths). • There are four sublevels: s, p, d, f

  41. Orbital Shapes

  42. Pauli Exclusion Rule • Maximum number of electrons in an orbital is two.

  43. Orbital Sublevels • Electron movement determines type of sublevel. • Electrons need energy to move in these sublevels.

  44. How many types of sublevels are in each energy level?

  45. Orbitals and Periodic Table

  46. m- Quantum Number m –number: • The number of orientations for each sublevel. • Sublevel Orientations: How many ways an electron can make a sublevel in 3-D space.

  47. S-Orbital Orientation • How many orientations are possible for s-orbitals?

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