L30 : Magnetic & spin quantum number - Structure of Atom, Class 11 Video Lecture

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that you have watched part 1 - part 29
now in talk about 980 quantum number it
gives the information about the
orientation of the orbital till now we
have seen the L the ethyl quantum number
gives the shape of the orbital whether
it is a S shape P same D shape this guy
gives the orientation of the orbital
with respect to quadratics for a given
sub have 2 L plus 1 values of M that is
minus L minus L minus 1 and s 0 to L
I'll explain in that example value of L
is 0 here right that means s so number
of orbitals is 1 this guy is 1 so I can
have values from minus 1 0 and 1 number
of orbitals is 3 this guy is 2 I can
have values from minus 2 minus 1 0 +1 +2
how many 5s 5 so that's how so if you
see this is my s orbital for s orbital
there is only one ship then I have P
orbitals for p orbital I have three
ships 1 2 3 - your intention actually
for D orbital if you see I have 5
different orientation 1 2 3 4 5
let's plane in detail for all these just
understand that for s there's only one
orientation for us s this will be one
orientation for P there are three
orientations for D there goes s this P
is for D they are 5 voltages similarly
forever their similar orientation and
cut mine at the Gorbaty let's take a
overview now for example this is my p
orbital so you can see the way it is
done this is P X which is where it is
inclined
X P Y because this guy is in y-axis this
guy's PZ we have P orbitals in four
different shapes this is one way
everything is combined nightly all P XY
is combined and if you see this is 1 s 2
s is bigger px is this way py is along Y
axis PZ Islam's a Texas
so now if we talk about D so d if you
see for D we had five five different
orientations this guy's d why is that
because Y Z is the plane that I have
this orbitals this is DX Y because X Y
is the plane where I have this orbitals
this is D XZ because xn is the plane
where I am so all of this is the XY
minus y square x and y like this fashion
and this D Z square because of them
ZX search the five different orientation
of the D orbitals
similarly for F also we have for F I
think we have sin 7 different options
and this is all seven different
orientations are there for F right if
you see or I for ever it is but their
orientation is different so magnetic
orbital number when you combine the
orientation of this organism there is
something on electronic spin also as I
told write each and every here my
orbital will have two electrons you
elect let's say I have two electrons
maybe this girl everything will have two
electron this whole thing will have two
electrons somewhere only to this one
orbital this lab two electrons somewhere
maybe both are in the same area also you
don't know right which is each and every
will have two electrons jumping in
pumping in on here there right so since
there are two electrons each may have
different spins in fact both will have
different spin one clockwise one
orthogonalize and that is
denoted by spin Cottenham so three
corner numbers which we have got n l m n
principal quantum number as with the
quantum number magnetic quantum number
they are not sufficient to take trade
the atom they are sufficient to predict
the or to pink on the orbitals say it
with n LM n NL and M we can tell which
orbital it is but in orbital we have two
electrons so we can't tell which
electron we're talking about so we have
a more modern one called spin quantum
write both all this quantum number like
are enough Twix are not enough to
explain the line spectra which is
observed in the case of multi electron
so we have this third quantum numbers
because to find the exact electron beam
the food attribute also so this guy in
1925 proposed the presence of four
quantum numbers that's caused electrons
spin quantum number it can have two
values plus 1 by 2 and minus 1 that's
all so you see electron spins around its
own axis it can be clockwise or
anti-clockwise and that's wrong it is
denoted so if you see it's a plus up
spin or down spin and the values is plus
1 by 2 and minus 1 by 2 because electron
spin this is electron the spins of the
right can we have a clockwise or and if
you only do off so it has no orbitals
cannot have more than 2 electrons and
these 2 electrons should have opposite
spin please note one orbital I have told
already cannot have more than 2
electrons and these 2 electron should
have and for this spin at the max 2
electron that it can have one electron
also the valance electron orbitals
generally have one lipgloss so let us
understand the quantum number three B so
let's suppose we'll start from here so
we have quantum numbers right so it can
have a value of
and can have a say in here and and can I
have a value of one it can have value of
two you can have value of three or it
can have value of small awesome correct
if n is going to one my L can have value
only zero because it has to be 0 to n
minus 1 here and n is equal to 1 l can
have two values 0 and 1 if n is equal to
3 and can have three values 0 1 & 2 so
if R for my L will be 0 1 23 possible
values for n if you talk about M for L
is equal to 0 M can have only one value
0 for L is equal to again for 0 again a
believable for a for 1 it can have 3
values minus 1 0 and plus here also if
you see for 0 it can have only 1 value 0
or this guy minus 1 0 and plus for 2
also it can have 5 values of minus 2
minus 1 0 +1 +2 like that it will
continue here also we can continue now I
am something called spin quantum number
right this is called spin so for this I
can have two well as plus 1 by 2 n minus
1 but it if I for any of these I can
have 2 values plus 1 by 2 n minus 1
right or the issue of these right I have
two values plus 1 right 2 minus Omega
plus 1 better and that is how the tea
structure for a quantum that means for a
given number like this this if you take
this path right I can tell one electron
example if I know this this this and
this these four values we will uniquely
give a particular electron and these 3
values and lemon will give a unique
orbital correct
let's take a summary for the four
quantum numbers we share the study use
something called cells subsets and
orbitals and end n define the cells also
determine the size to a large extent the
energy and there are n cells in the NF n
sub cells in the NF cell as I have done
and there L and defines the sub shells
also the shape of sub shells so L is
something is defined that and then we
have all Brittles right and the orbital
is nothing but 2 L plus 4 the number of
orbitals we have for example 4 s I have
one orbitals for P you have 3 orbital
for D you have 5 of orbitals and so on
l also determines the energy of electron
in multi-electron atom so the rules are
complex but for our understanding you
can say that n plus L will determine the
energy of and already the one with
higher value of n plus L will say that
that has more energy and this magnetic
quantum number designates orientation of
orbital so for a given value of L my M L
has to L plus 1 values right and M s
refers to orientation of spin on
electron this is what we have studied
we'll take some examples what the total
number of orbitals associated with
quantum number 3 so let us take this in
my n is going to three my L can have a
loo 0 1 n 2 right
I had to find number of orbitals so my
PE file for 0 I have only one orbital
for this guy I have orbital -1 0 n plus
1 or 2 I can have orbitals
- 2 - 1 0+1
cluster so if you add home now beetles I
have got 1 2 3 4 5 6 7 8 9 so there are
9 orbitals I have also I can use a
formula directly n square is nothing but
the number of orbitals so n is equal to
3 I get 3 square that is 9 or if it is
you can use any of these correct but
understand both the method because this
clears your concept thank you visit exam
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