In
our previous blog, we talked about Rutherford's model of atom. According to
his model, protons are concentrated in the center in a small volume of the atom
and electrons are revolving around them.
The Irish physicist, Joseph Larmor, published in 1895, the first analysis concerning radiation by an accelerated charge based upon the derivation by Hendrik Lorentz of the force experienced by a particle due its charge field being dragged through the ether.
According to this analysis, the revolution of the electron in a circular orbit is not expected to be stable. Any particle in a circular orbit would undergo acceleration. During acceleration, charged particles would radiate energy. Thus, the revolving electron would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable and hence matter would not exist in the form that we know.
In
order to overcome the objections raised against Rutherford’s model of the atom,
in 1915 Neil Bohr modified the Rutherford's postulates in order to prove his
model stable.
He put forward the following postulates about the model of an atom:
- Only certain special orbits known as discrete orbits of electrons, are allowed inside the atom.
- While revolving in discrete orbits the electrons do not radiate energy.
These
orbits or shells are called energy levels. These orbits or shells are
represented by the letters K,L,M,N,… or the numbers, n=1,2,3,4,….
These postulates eliminated the objections on Rutherford's model of atom and stablished the final atomic model. And
this is how the final atomic model was proposed. Since then, we are still
operating on the same model.
In our upcoming blogs, we will discuss about distribution of orbits inside the atom. Until then, try propose a better alternate model than Bohr's Model.
Fore more details refer to Beyond Reaction: Fundamental Chemistry
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