In 1916, Sommerfeld extended Bohr's atomic model with the assumption of elliptical electron paths to explain the fine splitting of the spectral lines in the hydrogen atom. It is known as the Bohr-Sommerfeld model. For more information on this topic, kindly refer this article; https://jayamchemistrylearners.blogspot.com/2022/04/bohr-sommerfeld-model-chemistrylearners.html

1. BOHR ATOMIC
MODEL
SOMMERFELD
MODEL
In Bohr's atomic
model, the electron
revolves around the
nucleus in stationary
circular orbits.
In Sommerfeld extension,
the path of the electron's
rotation is an ellipse with
a major and a minor axes
of 2a & 2b lengths.
Bohr expressed the
electron's energy
with the principal
quantum number n.
In Bohr’s atomic
model, the electron's
velocity is much less
than the speed of the
light. Hence, its
motion is non-
relativistic.
Sommerfeld
explained that the
electron's energy
depend on both
principal & azimuthal
quantum numbers
V E R S U S
COMPARING THE TWO ATOMIC MODELS
It didnot explain the
fine structures of the
hydrogen spectrum
In the Sommerfeld
model, he assumed
that the electron
travels at nearly the
speed of the light.
Hence, its motion is
relativistic.
It explained the fine
structures of the
hydrogen spectrum
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