L1 : History of Atom - Structure of Atom, Class 11 Video Lecture

hello friends this video on structure of
atoms part one is brought you by exam
fear calm no more fear from exam in this
lesson we'll study we'll know about the
discovery of protons neutrons and
electrons and also their characteristics
you let's try it some Thompson
Rutherford and both atomic models will
understand dual energy of electrons will
understand the important features of
quantum mechanical model of atom we will
understand the nature of electromagnetic
radiations and the Planck's quantum
theory will explain the photoelectric
effect we also describe atomic spectra
will stay that de Broglie relation in
Hinesville uncertainty principle will
define atomic orbitals in terms of
quantum number will state of bow
principle Pauli's exclusion principle
and Hans rule of maximum intensity
we'll also learn how to write electronic
configuration of atoms so how do you say
this we'll start the chapter the first
question that should come to our mind is
what is atom atom is nothing but it is a
basic unit of matter please note it is a
basic unit of matter and this consists
of nothing but a dense central nucleus
surrounded by a cloud of negatively
charged electron so if you see atom
looks like this this is my nucleus this
is dense is very small and then whatever
space you see the extra space here right
it's all weekend it's empty space with
electron dangling from here to here here
to here like this they all empty space
the only dense thing is this guy this
guy on the right and whatever extra you
see is all nothing but the space where
you have a high probability of finding
electrons so the way you find electrons
is always probability and that's how the
atom looked like so if you see if you
compare this dot or the nuclei of the
atom with a cricket ball this size of
the atom is nothing but a sphere of
radius Fight Club
understand the huge thing here this is
very small if this is a cricket ball
this is five kilometer that means in the
atom most of atom is nothing but empty
space
please note most of the atom is nothing
but empty space this is most of that but
I'll say 99.9% the atom is nothing but
empty space and then you have small
person very very small percent know you
have this nuclei which is dense which
has protons and neutrons and then you
have a dinner probability of finding
electron somewhere here or here and to
keep moving we will understand this when
we discuss the quantum model of atom how
the atom is or how the electrons are
distributed across this atom but let's
understand atom is nothing but the basic
unit of matter and then I see basically
de Madrid I need to say if I have atom
with a particular configuration with
that I can say that this particular
object will have X chemical property or
X or Y physical properties so those
things we can determine easily if you
know the structure of atom so they are
the basic building blocks of a matter
right and they're nothing but 99.9%
empty space and very tiny amount of a
tiny nuclei with a hell lot of space
empty space when electrons move around
the jump around and that's all electrons
all about it's all 3d it's in the fair
pong sphere please note it is 3d its
three-dimensional it is not
two-dimensional it is not like a plate
it is like ball just like a ball it's
three dimension it is like a ball right
it is like a ball it is three
dimensional spherical shape now I told
what is an atom the quotient comes again
why study atom why should we should I
study idea what will happen if you don't
say yeah so you can see the things which
we use for example coal the plastic
bottles
so the fabric the tires tea coffee
medicines everything is Adam if you want
to understand the chemical reactions you
need to understand Adam right you see
lemon balls Apple car the pencils
erasers use everything has right so if
you break any of these into small small
part example if it example and you break
you break you cut this Apple you get
this much pie you can cut this you again
cut this and then you find something
very very small this matter actually you
can't see Adam to make it eyes but that
the building block of this any any
matter so with Adam if you know the Adam
with which this Apple has made you can
tell about the characteristic of this up
or any object in the object so so if you
know Adam if you know the properties of
Adam you can tell the property of the
object which is made of the Sangam so
Adam is really critical to understand if
you understand the Adam you understand
the chemical reactions and the munis and
the chemistry so before we understand
the actual picture of Adam which i've
shown in the first again slide let's
understand the history of Adam how this
Adam came into picture because I mean
the processes are not born I mean it
takes time to evolve definition of Adam
and same thing happen so let's start
finish your honor
so in 500 BC this guy Greek philosopher
Democritus this guy told that Adam is
nothing but uncuttable and the word Adam
in Greek Nissan kettle he's he told that
you take anything for example you take a
mango right you cut this mango you keep
cutting you keep cutting it to the last
point you find a point where you're not
able to cut that with the best possible
instrument you have and that thing will
be out that's what health definition was
right you you take any object you keep
cutting it keep cutting it and you reach
a point where you are not able to cut it
further that particular thing is Adam
and provided it you don't cut it mind
you have best instruments to cut
right in that case that is Adam Adam is
something which is untouchable this was
a definition given by democratise in 500
BC and that was a time and the word Adam
came into because before 500 BC the Adam
word was not even there nobody knew what
Adam is right this guy gave the word at
then in 1805 if you see almost 700 years
after this because this guy gave some
Adam but the business is a philosophy
there was no there was no experiment at
this point of time well just a
philosophy some people you should
believe ate some people is to oppose it
this guy in 1805 he proposed atomic
theory and he had some experiments done
to prove this so this time does not
philosophy it was experiments right this
till 500 PC you know like all philosophy
that there is something of a term which
is uncredible but in 1805 John Dalton he
proposed an atomic theory and then in
1850 and and explained what John Dalton
through is just after the slide and then
in 850 this guy
Faraday he found something called
cathode ray tube and with that it was
easy to discover electrons the electrons
when discovered and then this guy
proposed a model 1909 to other a fool
Thomson proposed a model and then in
1909 brother Ford proposed a model of
elect will it will even really go
through all this model one lemon and
then this model had lot of demerits then
1912 Bohr proposed model and please note
all these models are not correct till
now and then in a hint to elbow propose
to model it
it could answer all of questions but
still this model is not appropriate and
please note when the bull proposed this
model in 1912 he assumed that electrons
are charged particles right he assumed
electrical just particles will explain
in the next slides or next few slides
drones are not holy particles they are
dual in nature they have way property in
particle property they explain that hold
on to that and then 1924 this guy dee
broglee gave a hypothesis on the dual
layer of electron and 1926 we're here
this guy's Hollinger he proposed the
equation that can tell the path of the
electron where the electron moves and
with that they came with the quantum
model right in 1927 I get this by
Hinesburg he proposed the uncertainty
principle and in 1932 Chadwick found the
neutron and then this guy found the
quantum model after this it is not in
this slide but this is the model which
is mostly accepted this was found after
all this happened these guys proposed a
model called quantum model of atom
quantum model of atom and that is the
most widely accepted model for add-on
today right we're all models thumbs
model to the foot model Bohr model all
these had issues they're incorrect the
correct model is quantum model operator
please please understand this the only
correct model is quantum model or finder
all this models rather food bore and
chances are incorrect model apparently
just telling this because you want to
study the history of atom but
experimentally you can prove that all
these three models are incorrect if I
have plenty of models to possess one
equal but we'll be studying only the
three models and I want to reiterate
that these models are also in correct
they're not correct the only correct
model is quantum model ah thank you
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