Modern periodic table - Elements & Periodicity Video Lecture - Class 11

hello friends this video classification
of elements part 6 is brought here by
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before watching this video please make
sure that you have watched part 12.5 now
let's study the one their activities in
muslin see this guy mostly in 1913 he
shorted atomic number is a better
fundamental properties in atomic mass
and please note atomic number itself was
formed by this guy because till 1896
nobody knew what electrons the atomic
mass was all found by takeo metric
equations by chemical reactions 1896
this guy function is a function for
electron and then at that of the area
where radioactivity was at peak and this
guy was a physicist and he was able to
find a number of electrons in a
particular element by the Rays intimate
okay where is it emits so with that he
was able to find a number of elements
number of electrons and there is nothing
but the atomic numbers Nene was he
coined this what an atomic number and he
found that all the elements and then he
observed that if you use atomic number
instead of atomic mass in the periodic
table as used by mostly it overcome lot
of limitations correct and that's what
he did also electronic configuration is
a perfect basis for classification of
element so also used because there are
the property that all the elements in a
particular period sorry yeah will have
similar electronic calculation so with
that we'll explain more when we learn
when you go through the detail of this
table but this an electronic
configuration of the public elementary
the perfect places for classification of
element
periodic law can be sealed as properties
of element or Theory function of the
atomic cover that is spend some more
time on the electron configuration for
example I have element which has
electronic ways not to eat - that means
this guy is first second third third
period right and this guy but really the
group number okay a second that means is
a second - this is my element I'm
talking about let's suppose I have an
event two three they are two first
second so it will be in second period
two and three so this guy is three so
three is thirty right so this is guys so
just by electronic application you can
actually tell the location of the
element in the character it explained
more on this but just understand what
this guy atomic number did with the
mostly fit electable right 30 David
thing the first thing is the position of
isotope is clear now why because isotope
you see that all these elements have
same atomic number example c6 I do you
have 12 13 and 14 but if you see all
this have Sandra atomic number since
they have similar atomic number they
will be only one place for carbon
correct and this one so since it is no
longer based metal make mass there is no
confusion of I stops the position of
chabad and nickels clear not you see the
Chabad and nickel is not properly
arranged right when you talk about the
atomic number they are properly arranged
it producer in 28 but it docked about
that of a mass right so they have some
confusion because the atomic mass of
cobalt is more than ever big most nickel
if we talk about atomic mass may talk
about atomic number cobalt is less so
since I am empty since I am using atomic
number now right so
issue is unresolved position of hybrids
it explains because as I told it is done
by the electronic configuration if you
see hydrogenous Tomic number is one
electronic company is also one that
missing the valence cell now most
balance and it has only one electron so
it is in this all their bits are present
which has one electron in the outermost
shell so that is the god of position for
hydrogen because the formula for
grouping is different now it is not
based on the hydrates in the oxide form
but actually it forms similar hydrogen
oxide but it is based on this electronic
cutting machine and also answer this
question that whether it is possible to
have an element of atomic number 1.5
between hydrogen helium we can say now
know why because atomic number is
national number right we can't have the
national mobile good fight correct so
with that this question which was not
answered that time this or not because
atomic number is international number
national number count 1.5 that means if
i say that how many elements can be
between one and five let's suppose of
one and six then you can see that they
are element between minus six
now if we talk about atomic numbers but
if you are talking about atomic mass you
can that one point two and five point
eight they are not big mass of two
different elements
how many limits can be there between
these elements you don't know because
they all decimal numbers right so this
question will also answer to this now
only one connection there is using
atomic number instead of atomic mass
sort so many issues so the modern
periodic loss is that the properties of
the lipids are periodic function of the
atomic number three so there is a coming
number not recommend mass right so the
piece of this law is that when elements
are arranged in increasing order of
atomic number
having seen valence electron when this
occurs the Reagan they were in trouble
so the outermost electrons out of my
shell the number of electrons now too
much less common electron so there is a
it follows a periodic function we keep
increasing the if you keep arranging the
elements they're coming releasing enough
numbers so we see that this elements
with the same number of valence
electrons or convenient example hydrogen
if you see has one right let me I'm
helium in the school then you have
lithium again that has one right so the
way that's why it is then the billion
boron carbon nitrogen oxygen so if you
see I'll show you the team in follow the
periodicity so let's see this northern
variety of n elements are based BC of
the electronic calculator and they are
18 vertical columns one of the groups
waiting rooms and seven horizontal rows
and they are known as PDFs if you see
here periods periods want to leave like
this and then they have groups correct
why it's called groups just for the
memory tip two and understand this they
have called blows because this group is
highly improper me just to same property
so if you tell a group because they have
same thing same right some chemical
probably the same so all these groups
have same and that's why they're called
blows if you think this bunch of
elements they don't have same chemical
property and that's what they never call
broke it so group has same cubic a
property and that's happened when you
take the you take the punch in this
fashion right and that's why they call
groups correct these are called periods
as I told our modern periodic table has
creates and groups let's understand the
period in DT so holiday the rows of
elements in a periodic table are called
periods correct example this is one
period this
and there are some properties of PA for
example every period has contributed by
atomic number to example this is 11 this
guy is 12 this case 13 14 15 like this
right so the elements in this period
will have conjugative atomic numbers
also the number of elements in the
period is fixed by the massive numbers
of electrons which can have the valence
shell example the first guy I am NOT
written here this hydrogen and this
helium so they have two so first is to
only two maximum elements can happen in
the the second is a lithium lithium one
is eight and then we have this guy
sodium magnesium oxide as the age
this guy has 18 right so then I'll
divide the number of LA as the number of
elements the number of elements is
nothing but the maximum BER of electrons
is up shells the out of our shells and
all the elements in a group has same
number of shells because they have
similar electronic configurations and
the maximum power of electron that can
be accommodated in the sheer liquid
whose formula you know this formula you
n Square where n is the number of shells
correct and it is the valence electron
which will be the first and is the
valence electron which decides which can
be the first and rich guy will be the
last example the one with a one-man
electron will be the first the one with
eight valence electron last correct
exception is the first one where he M
has to I mean you know say that the one
with the one valence electron in the
first and the one which has all the
valence electrons fill is the last see
this first period if you see it has only
two elements hydrogen and hence called
very shortly
she the second guy it has age limit
lithium beryllium boron carbon nitrogen
oxygen
this guy has eight he's nasty they're
also called short one similarly the
third one sodium magnesium aluminium
silicon phosphorus Okanagan it also has
eight also called short and then you
have a long one this is 18 he's
graduating yesterday also has 18 right
this guy has six has 32 say it keeps
increasing yeah I mean they are seven
doublings oh this guy has the one which
is found also so that's right there so
you see that we have different periods
the first period is a very sharply then
shot and shot then we have long enough
and then we have very long and very long
again so yes every it's an and if you
see this all depends on the 2n squared
formula is 2 8 8 is knitting 30 now
let's see groups these are all call
groups because they have same chemical
property so if you see vertical columns
in the periodical ropes and please note
they don't have a consecutive atomic
number if you see is my in 1735 they
don't have consumed it number as we even
periods and they have seen valence
electron though you see helium two
electrons on one leg my neon two
electrons are gong to or everything has
two electron minus eight so sorry this
is by exception here this guy has two
but apart from these all as eight
valence electrons you see here everybody
has one valence electron this guy is one
lethal is to one so name is two eight
one - Amos - 8 10 8 1 right if you see
each and every I had one valence
electron so here also but a chameleon an
exception because he'll Ian's cell is
filled with two atoms so but apart from
that all eight heroes if you see it is
seven
this two billion seven later all arson
they have similar electronic electronic
configuration they show similar physical
and chemical property that is the main
reason why their cloaking first can see
critical properties they have similar
physical and chemical power and the
number of shells increased as we go down
if you see this guy has one shell this
guy I stood there three in squares for
the number of shells increase as we go
now so position of hydrogen at all right
position
this guy is placed here because it has
electronic configuration similar to our
climate and we know that electronic
configuration is a critical thing to
arrange the elements so there is no
confusion now where hydrogen should be
in but actually if you see hi rahem is a
nonmetal the greens were the nonmetals
and it is placed with a type the
hydrogen's plays with alkali but the
property of hydrogen is not similar to
alkali because it's very small in size
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