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Unformatted text preview: lar momentum of the electron is quantized.
• angular momentum = mvr = nh/2π
h = Planck’s constant n = 1,2,3,4,...(energy levels)
v = velocity of electron m = mass of electron
r = radius of orbit Postulates of the BOHR ATOMIC MODEL:
1. An atom has a number of definite and discrete energy levels or
orbitals in which an electron may exist without emitting or
absorbing electromagnetic radiation.
As the orbital radius increases so does the energy
1<2<3<4<5...... 3 1/21/2014 3. An electron may move from one discrete energy level
(orbit) to another, but, in so doing, radiation is emitted or
absorbed in accordance with the following equation. Atomic Spectra and the Bohr Atom
Bohr’s theory correctly explains the H absorption/emission spectrum and
other H-like species.
The theory fails for all other elements because it is not an adequate theory. Emission spectra for Iron
of ER Emission
of ER The Wave Nature of the Electron
• In 1925 Louis de Broglie published his Ph.D.
dissertation that describes how electrons
have wave-like properties
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