Chemistry Periodic Classification of Elements part 5 (Mendeléev periodic

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classification of elements part 5 is
brought to you by exam fear calm no
words for you from exam before watching
this video please make sure that you
have watched part 1 part 4 now let's
understand the mentally period cheville
the the best periodic table I can say
the best effort so this guy what he did
was he arranged the remains based on
their fundamental properties atomic mass
and also based on the chemical property
but chemical property was given the
first priority so at that time there
were 63 elements known so he his work
was on this 63 elements he first tried
to find the relation in atomic mass and
the chemical and physical property and
to find the chemical properties
relationship these are look at the
hydrogen and oxygen as because they were
very reactive and they form compounds
with most of elements so they he reacted
most of element with hyper to the oxygen
and the way it react with hydrogen
oxygen example this is somebody's X and
it reacted with hydrogen it gives
something in X reactive oxygen it get
something right it may be our n maybe X
H maybe x h2 right maybe in this case
maybe X 4 it can give X 2 or it can give
X or 2 right
it can mean X 2 or 3 based on based on
the property of the element right so it
can react in different ways so similarly
with hydrogen also can react in
different ways it can give xs-3x h4 so
based on the reaction of the element
hydrogen oxygen he grouped the elements
correct and then he also used the atomic
mass to arrange them correct so that is
the formula of hydrogen oxide viescha
gate the hydrating oxides formula which
again was one of the critical parameter
for cross section element so what he did
was actually for he to for example 63
elements right blue Lito 63 card in each
of this card he lured this element named
his a mother a male element
is X and this guy formed some head right
accent' and some oxide x coordinates of
the right and atomic masses that suppose
in 58 let's anything so this guy he
agreed cards like this he created 63
cards like this with all the 53 elements
named and all the hydrides and oxides
and all the atomic mass once he had all
these values right he know all the 63
elements named you know the atomic mass
of all the elements he knows the hydride
the oxides form now he grouped these
elements based on these hydrogen oxide
they are the critical thing you see to
see the last one the newline love active
he arranged beach on the atomic mass
alone right so his his his parameter was
atomic mass and then he found that they
have similar canoe tonic but this guy
for him the critical thing is chemical
property and then he he's trying to
erase the atomic mass right and if he
finds a missing object he has created
gaps also in the tables they explain
that but let's understand that both have
a different approach the Newlands one
what it was his his primary concern was
the increasing atomic mass and then he
found that coincidentally they have
repetitive chemical property for this
guy the critical or the main thing was
it should have same properties chemical
property than is the kind of hydrogen
oxide form should be similar and then
the second critical thing was up atomic
mass all right
so he started these elements based on
the similar properties and also that
most of the elements got a place in the
favorite table to be arranged in the
order of atomic mass increasing atomic
mass so he was able to arrange them
correct and he also observed the
periodic recurrence of elements with
similar physical and chemical that's
what what Newlands have observed he also
observed here also correct and in for on
business of all his experiment he did he
he gave a periodic law right and you say
that the property of the elements
a periodic function on the gamma this is
the law he gave this law is called
mentalists periodic law it says that
property of the elements are periodic
function of atomic mass please note it's
atomic mass we don't need the atomic
number now because atomic number is not
even discovered by this time I introduce
the electrodes was not discovered all
the atomic mass which we use here it's
all formed by its the chemical reactions
because the base of all this was the
Dalton theory the dawn dodging gained
this during 1804 very told the mask and
neither be created nor destroyed and in
that documentary equations they found
the chemists from a lot of atomic masses
and these was the atomic mass was used
by Mendelian I hope it is clear to you
so what he has done was he reacted these
elements with hydrogen oxide he found
different hydrates different oxides and
based on the hydrogen oxide found he
kept these elements right and then he
arranged this elements based on the
increasing atomic mass keeping in mind
that all this form which forms similar
hydride oxides are in a similar group
I'll take the picture with that I think
it will be more clear example if you see
the hydrates can be hard to open instead
of X they are using are here or ro R - o
3r o - R 2 O 5 r o3 r 2o 7 + r over the
different kinds of hydride he found and
then he clump all these elements right
and then hide the oxides for hydrides
are h o h2 or h3 or h4 or s3 RS 2 or H
these were the hydrates so based on
these two we cops example for these
combination he found these many elements
say Club all these into one group
correct all this into one group all of
the matter so he he grouped elements
like this correct and then if you see he
he called his vertical columns as group
so this guy's girl groups so group 1
group
to group three and these were all
periods may they all be the he called
this use this word groups infinitely
share also used in the model reelect
evil so but there's if you see
everything is Adamic mass here hydrogen
atomic mass and then so if you see
there's a lithium beryllium boron carbon
nitrogen oxygen fluorine all the atomic
mass right and we asian the properties
this is what the kind of periodic table
he formed which was pretty good
very very few limited in that but was
very good actually
so we'll explain the merits and demerits
of these periodic table so let us do
this hope you understand how he found
the spirit table so let's understand the
achievement of this multi period table
first thing is rated sound elements
which are not discovered at that time
because when he arranged the elements he
found that some elements of are missing
because some of the elements atomic
possible missing and then he guessed it
he guessed that okay there will be
atomic element which will be found in
your future
we should have atomic mass of 68 and he
called that guy as a car aluminum
because it used to come with aluminium
and that element was found in future and
we call it 11 that element does kalium
and he also what he will guess the
formula of oxides in chlorides if you
see he guessed that that particular
element which will have a formula of e 2
O 3 based on his periodic table and
that's what it it was he also gives the
formula of chlorides or hydride to be
like this that is e CL 3 and we found in
gallium also follows the same sciutto he
guessed the existence of sun element we
should not disguise a time not only the
existence of the element but also the
physical not physical chemical property
on the elements he could predict
properties of several elements peas or
they pushed as I told these elements
right I mean they were elements for
which the property was
form but these are the position you
could tell um if this guy will form
hydrates in this fashion this guy will
form oxides in this fashion so it
because if you've seen his periodic
table is all based on the oxides and
hydrates right you see the way it is for
example this guy he is not reacted you
don't know how it reacts but just
because this guy is in Group four seven
he can say that this guy will form oxide
like this it will be PR two seven and
will form hydrides like this the edge so
that's what the the purpose is right so
in this case let's suppose is very
difficult to react this guy with oxygen
at that point of time so what he don't
okay I don't know how to react but but I
know that this guy la will react with
oxygen to form something like la both
linked and if this guy reacts with
hydrogen forms will be like elastic and
that was true also if we had those
things in chemistry lab and you see that
that was the kind of reaction goes
through right so so just by looking at
the position of the element for example
TI so 10 if react with oxygen if it
reacts it will form TI u 2 and if it
reacts very importantly i actually know
the way kind of things he was able to
tell just by looking at the position of
the element in the periodic table also
he could accommodate normal gas because
these gases were discovered at that time
only so once he was done with the table
after that the noble gases where this
court but he was able to accommodate
that so his table was able to equivalent
that there was one good thing about his
Stephen now let's see the limitation of
this table the first thing the isotopes
may also discovered that time when this
noble gas were discovered
but the position of isotopes could not
be explained as I told as isotopes are
elements with the same atomic number
right at the fennec mass if you see this
is all love I suppose carbon twelve
thousand forty so since they were
different uh big mass they should be
different they should be placed
differently the table right but that's
what not crystal
loud is to be loud only comment in
please once so the position of isotopes
could not be explained that time right
so this was a I suppose were discovered
after a long time of the men Lee
proposed a spheroid table but once I saw
how Square discovered these I suppose
could not really get placed in
collectible and then I was not very good
collect also some order of atomic mass
was wrong naturally in some case and
that could not be explained
for example the cobalt cobalt was 4029
it came before nickel and nickel is 50
27 this guy came it is like this 50 8.9
km/h 58 27 key there was a debate on
this white is happening like this do it
were the only point to difference but
jelly it should be forced to become then
second and third like this right it
should not be the other way so the the
wrong atomic mass order was not
exclaimed at that time right also
hydrogen was not assigned a correct
position because hydrogen has the
property both of alkali metals and
halogens so if you see hydrogen believed
behaves like chlorine more times and
also behaves like sodium right so what
should be the position of hydrogen was
not confirmed because his classification
groups was based on the wave element
react with hydrogen's right or the
memory element react with oxygen right
so with this hydrogen behave both as
alkaline halogens so the position of
hydrogen was not clear also we could not
ask this question is it possible to have
an element coming math3 between hydrogen
here for the position for example
hydrogen has a living must one helium as
the suppose for right so can we have one
element at the week number three here
because atomic mass can be inning a bite
can be four point zero a four point nine
five right
so between let's say both 4 and 4.5 you
can't see how many atomic mass exists
maybe 4.1 4.2 4.0 you can't say right
but if it is something like numbers I
say that some party is number for
example it has to be numbered then I can
say between 1 & 3
they give me only one number that is 2
right but if some point is not numbered
because this guy is not number right
this guy's not sorry
this guy's aren't not national number so
this guy's not in this race this is the
number right so that is I can't see how
many decimal number Craigs is between
Pergamum for example between 4 & 5 I
between 4 & 6 tell me how many decimal
numbers can exist they can be mainly
because 4.55 5.2 425 there's so many
numbers bar between 4 & 6
how many the National McGee insist only
one all right so since atomic mass was a
decimal number actually is a non
national number so it was not possible
to tell if someone asked the question is
can there be in between hydrogen helium
the answer was I don't know because they
can be the K may not be right so these
kind of limitations were there with
modern clearing table thank you visit
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