L2 - Bohr's Model of an Atom - Structure of Atom, Class 9, Science Video Lecture

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Bohr's model of Atem there is models of
the atom have been proposed by eminent
scientists over the years these models
have increased our understanding of the
atomic structure among these models root
the food suggested that electrons
revolve around the nucleus in
well-defined orbits but there was a
problem with this the motion of
electrons in truth affords model was
unstable because any charged particle
moving in a circular path emits
electromagnetic radiation thus the
electrons would lose energy and fall
into the nucleus making the atom highly
unstable then which would be a better
model of an atom to overcome the
objections against through the folds
model of atom Niels Bohr in 1913
proposed a new atom model what does this
model propose it first proposes that
electrons revolve around the nucleus in
specific orbits and these orbits are
associated with definite energies and
are called shells or energy levels these
orbits are shells are represented by the
letters k l m n the maximum number of
electrons that can be accommodated in a
particular orbit is 2 n to the power of
2 where n is a number of the orbit the
sky shell would have two electrons and
shell would have eight electrons M shell
would have 18 electrons and end shell
would have 32 electrons and so on that
said what does this model next propose
it next proposes that the maximum number
of electrons that can be accommodated in
the outermost level is 8 and finally it
says that the orbit closest to the
nucleus has minimum energy and the orbit
farthest has a maximum energy well then
does an electron radiate energy by
itself since electrons move in a
particular orbit they do not radiate
energy by themselves what happens
instead is when an atom absorbs energy
the electrons get excited and jump into
the next higher energy level the
electron can radiate energy and return
to its original state or drop down to
the next energy level Bohr's model works
well for simple atoms and is easy to
understand it is one among the atomic
structures still in use today and the
other being the quantum mechanical model
things to remember in 1913 a Danish
physicist Niels Bohr proposed an atomic
model known as Bohr's atomic model in an
atom the electrons revolve around the
nucleus in definite energy levels called
orbits or shells the maximum number of
electrons that can be accommodated in a
particular orbit is 2 n to the power of
2 the maximum number of electrons that
can be accommodated in the outermost
shell is 8 the orbit closest to the
nucleus has minimum energy and the orbit
farthest has maximum energy electrons
are excited to the higher energy levels
by absorbing energy and return to the
lower energy levels by radiating energy
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