Bohr Model Of Atom
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Transcript of Bohr Model Of Atom
Bohr Model Of Atom
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
Continuous Spectrum
Line Spectrum of Hydrogen
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
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
Coulomb’s Law The energy comes from the potential
energy resulting from a separation between a positive and negative charge
Coulomb’s law describes this
q1 and q2 are the two charges
r is the distance between the charges k = 2.31 x 10-19
1 2q qE k
r
When electrons occupy the lowest possible energy level, they are in ground state
When in higher levels, they are in excited state
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
Equation
ΔE = Ef – Ei
hν = RH ( 1/nf2 - 1/ni
2)
frequency of light given off depends on the level transition
Example 1 Calculate the frequency and
wavelength of light given off when an electron in a H atom falls from n=4 to n=2. What color is it?
Ionization of Energy Energy that would be needed to
completely remove the electron; make it go from n = 1 to n = ∞
Example 2 Calculate the energy required to
ionize an electron from the ground state.