Bohr Model Of Atom

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Bohr Model Of Atom
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Spectrum

• Continuous spectrum is the rainbow of colors
  containing all wavelengths
• Line spectrum contains only certain colors or
  wavelengths
• When gases are given energy, they emit line
  spectra which are characteristic of that gas

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• Continuous Spectrum
• Line Spectrum of Hydrogen

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Niels Bohr

• Said electrons occupy the atoms in quantized
  energy levels
• Each level (orbit) is assigned an integer (n)
  called the principal quantum number
• As n increases, the radius of orbit is greater

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Energy

• Energy of the electron depends on the level it
  occupies
• En - RH ( 1/n2)
• RH is called the Rydberg constant
• RH 2.18x10-18 J

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• When electrons occupy the lowest possible energy
  level, they are in ground state
• When in higher levels, they are in excited state

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Hydrogen Line Spectrum

• H atom absorb a quantum of energy
• Energized electron jumps to a higher level
• When it falls back down, it gives off energy as a
  photon of light
• The frequency of the light depends on the levels
  it falls from and to

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Equation

• ?E Ef Ei
• h? RH ( 1/nf2 - 1/ni2)
• frequency of light given off depends on the
  level transition

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Example 1

• Calculate the frequency and wavelength of light
  given off when an electron in a H atom falls from
  n4 to n2. What color is it?

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Ionization of Energy

• Energy that would be needed to completely remove
  the electron make it go from n 1 to n 8

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Example 2

• Calculate the energy required to ionize an
  electron from the ground state.