Saturday, 27 June 2015

Bohr’s model for hydrogen atom and Limitation of Bohr’s model

Bohr’s model for hydrogen atom

=>  Explain by nails Bohr (1913).
=>  Postulates for Bohr’s modal are,
1.     Electron in hydrogen atom move around nucleus in circular path of fixed radius and energy. these paths are called orbits
2.     Energy of e does not change with time.
However, when electron move from lower to higher stationary state it absorbed sub amount of energy and energy release when it comes back.
3.     Frequency of radiations emitted or absorbed when transition of e occur is given by
bohr model
Where, e1 & e2 is lower & higher energy state.
4.     Angular momentum of n electron in given stationary state is given by
bohr model
[Where n =1,2,3.....]

Limitation of Bohr’s model

1.     Bohr model fail to explain finer detail of hydrogen atom spectrum observed by spectroscopic, techniques.
2.     It fails to explain spectrum of other atom except hydrogen atom.
3.     It fails to explain splitting of the spectral lines in presence of electric (stark effect) or magnetic field ( Zeeman effect )
4.     Fell to explain formation of molecules from atoms by chemical bonding.

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