Shape of orbitals - Structure of Atom Video Lecture - Class 11

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no more fluid from exam before watching
this video please make sure that you
have watched part 1 2 part Ludi shapes
of atomic orbitals if you see the
wavefunction which you have gone psy has
no physical meaning so if you observe
from a hi-fi micros form or something
you won't see the orbitals actually this
is something which you can't see well it
doesn't have any physical meaning it's
just probability function just a
function this is just a mathematical
function for the coordinates of later
however the differ for different
orbitals for a corresponding difference
the function is function to are are
different the shape of orbital which you
get from wave functions as a function of
R are different and the square of the
wave function gives the probability
density for the electron at a given
point example for one as if you see the
electrons are there at this point height
probability of finding electrons right
it goes off and then from here there is
no probability of finding each one but
two as if you see it start at this here
it ends here
it starts here there's a high
probability here right again it dips off
that means this is the range where you
get high variety of finding electron in
2's orbital for the 1s this is the range
where you get clarity you're finding
correct and we have regions where
there's a 0 probability of finding
electrons and they are called nodal
surface or call simply nodes so if you
see in this case I have 1s then I have 2
s this is my 1s this is my 2's this is
the reason between 1s and 2s and his
load because there you have zero
probability of finding electron for 3
years of you see this is 3 has a bigger
circle then I have 2 s then I have 1s
then if you see this two are the nodes
where I have zero probability of finding
electrons
like so knodel's up is a node other
place where we have zero probability of
finding a very less variety of mining
shapes of the atomic orbitals as I told
I it is just a mathematical function it
doesn't exist really but if you want to
understand this you can draw a boundary
surface diagram already circuits like
this example in geography we have can do
diagrams and latitude language he's
doing exist right if you go to any place
you won't be able to find logic like
twin sister convention we have used to
make a life better similarly here also
these these things doesn't exist plot
one you're seeing doesn't exist they're
just the diagrams which we create to
make our life easy to understand
chemistry easily so the boundary surface
diagram of the constant prepared again
soon for a given orbitals give a fairly
good representation achieve on orbitals
this just give you imaginative shape of
the orbital so in this representation
what we do a boundary surface or a
contour surface is drawn in the space
for orbital in which the value of
provided is this constant example in
this case at this point this point this
point the probability densities constant
so I'll draw one line here also is
constant constant constant so I'll login
draw once again but the lighter color
because the color will design the
probality and thus if you keep drawing
you'll get something like this right
because if you see one dark dark here
the same darkness this way that the
probality densities probability is c to
get the electron in this reason this is
lighter that means you have less
primality up right so in principle if
you see there are so many boundary
surface to me possible so if you combine
this you get this kinda right and
generally we take the probability where
it's 90 percent hundred percent is not
possible right because if you see a
hundred percent that means you are sure
the electron exists the
and then it kinetics the Heisenberg
principle where you say that he can't
actually tell the position of the
electron so it can't be undone person
almost 90 person so we jelly talk unto
them get this kind of shape right and
boundary surface for a s orbitals
actually has a spherical in shape
example in this case if you see and this
is a two-dimensional it looks like a
circle in three-dimensional it looks
like sphere let's talk about the S
orbital shape of the size of s orbitals
this is my S orbital then I will show
you the movement of electron also all
the S orbitals are spherical symmetric
because they all spherical shape you see
this is how the electron moves in the
sphere if you see this electron is going
in coming out that's why you see the
size is growing and sinking also it's
moving so it's three dimensional motion
the electron can be anywhere anywhere in
the sphere
he made this sphere right and that's was
the orbitals all aboard please notice
orbital doesn't exist actually it's just
our this is relation to understand this
orbital in a better way so the size of s
orbitals increase with there are log n
so 1s has a small size two as bigger and
three as bigger and 4s bigger and
pictorially we see the radial node
appears to be a spherical surface unless
there is no electron density you see
there ideal or I told you something
where you don't have any electron Tacy's
chances of finding two where it is very
less the number of radial node is
nothing but n minus L minus 1 so 4s
orbital my L is 0 so for s orbital the
number of radial Lawrence n minus 1 so
if you see for n is equal to 1 there is
ZERO radial node for n is going to do I
have one radial node here for n is going
to three I have two radial load here
right
because 4s orbital L is equal to zero so
this becomes n minus 1 but this number
of radial load n minus L minus 1 in the
general formula for any kind of quantity
this SPAD these form lines say and
number of angular node is L in our case
for s orbital L is 0 there is no angular
node we'll discuss 9-yard node we will
discuss the P orbitals this understand
this general formula for radial node the
number is n minus L minus 1 general
formula and what angular node the
formula is and the number of radial
nodes let's take the P orbitals P
orbitals look like this
you see the electrons can move anywhere
there two electrons your witness if you
seen the s orbitals we also we had on it
to be electrons so there are two vectors
can move anywhere and it has two
sections called lobes so you see there
are two lobes Ashley neither side of the
plane and the probability of finding a
Tiberi density is 0 on a plane where two
loops touch each other this please also
there's a probability of finding 0
electron and the size shape of 3 energy
of 3 orbitals are same size same an
energy is same but the orientation is
different right the size say anything
the same nu also same but the
orientation is different and if you see
px py PZ are three different way of
noting this so we'll continue with P
orbitals so like S orbitals if you see P
orbitals also increase in size and
energy with increase in the quantum
number n that is 2 P 3 P 4 P the size
and energy is more for this movie also I
guess the probability density the
function for P orbitals also passed
through a value 0 right besides 0 at
infinite distance and those are called
the nodes Ashley the number of nodes
here is given by n minus 2 why because
the general formula was n minus L minus
1 here L is go to 1 this becomes n minus
2
the nodes is n minus 2 and the radial
load is was L general formula here L is
going to 1 the radial node is 1 right
sorry this is a radial node itself so
for 3p this becomes 3 minus 2 1 4 4 P
this becomes 4 minus 2 that is 2 the
radial node formula here is n minus 2
but don't remember all this just
remember n minus elements little formula
in this case L is 1 so this becomes n
minus 1 minus 1 is n minus 2 so 4 3 be
my n is 3 so already naught is 1 3 minus
2 4 4 P already known is 4 minus 2 it is
2 and so on angular node also is a
planar or a conical surface in which
there is no electron density for P
orbitals we have one cleaner known why
because for angular node I told the
number is L and in this case p orbital
they'll balance 1 so it will have only 1
angular node and since the energy of
each orbital is a function of only of n
right then all n is equal to 2 orbitals
have saying it so if you say 2 as 2 px 2
by tupiza they all have same energy for
hydrogen right but actually if you see
2s and 2p they have different energy
that depends on n plus 1 multilateral
the number of radial node is given by n
minus L minus 1 and if you see for p
orbital LS well - once this becomes n
minus 2 we've covered this in the number
of angular nodes is given by L C for P
orbitals
air is equal to 1 so the number I will
notice all this what this is also cover
next take D orbitals know the orbital of
you see it's like this this also will
have 2 electrons
they'll be moving in sorbitol right for
this L is equal to 2 and the minimum
principle quantum number for this is 3 y
3 because 4 L is equal to 2 the minimum
value of n has to be 3 correct because
le cannot be greater than n minus 1 they
are 5 values of M L minus 2 minus 1 0
plus 2 plus 1 and that's why he have 5
different shapes for D ordinates all the
orbitals have equal in energy and all 3
D orbitals I'm telling the D orbitals
for which n is greater also have seen in
shapes similar to 3 D orbitals but the
energy inside little shape is same but
the energy inside is different for
orbitals which are greater than P
feasible for D Phi D they have same
shape but the energy and sizes differ
the radial node besides the radial load
the probability density function for n
p9 near zero at planes passing through
the place and they are called angular
nodes right and for this triangle notice
L 4 4 D orbitals a value of L is 2 so
they are too angular
now let's take the overview of atomic
orbital be able discuss that Omega
orbital let's just let's take the same
picture once again and discuss things so
we have in this case we have this is my
1 s this this spare is 2 s then I have 2
piece 1 there 2 P Y 2 PZ and then I have
three years in each of these will have
electrons if you see all these moves
this is not moving because I drawn this
so these three years also will have to
be electrons which mean somewhere moving
around here and there I did you see the
black one moves only in this particular
p orbital the yellow one if you see
moves only in the 2's orbitals the green
one here moves only in 1s orbitals right
you see the red ones move only in this
particular geometry and that's how it is
do you have to pin orbitals and if you
grow on if you have one more 3s if you
have 3 P again we have to draw something
like this here the big ones
oh I can draw this will be something
like this so this two then I have
something called 2px 2py and something
like this so it will make P right so
this is my team this is V by 3 P and so
on in the carrying on a building I have
3 D also then I have to draw something
like this you know only this is a start
from origin actually alright that's how
the look and feel of this I hope with
this you get the clarity of how the atom
looks like in the real world
thank you
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