Alkaline Earth Metal Trends Video Lecture - Chemistry Class 11 - NEET

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what are alkaline alkaline earth metal
so we have discussed the alkaline earth
metals are nothing but the group 2
metals all these metals beryllium
magnesium calcium strontium demon and
they have a trend in the property should
discuss also they the barium the the top
element of this you could the first from
the rest of the elements and it has
properties similar to aluminum that is
the group 13 elements we will discuss
all these things let's start with the
trends so similar to alkali metal alkyl
minor metal also show trends in the
physical and chemical properties
you think recent atomic number and we'll
discuss electronic calculation I don't
make a 930 years will discuss on again
pallfy hydration the LPR conditions to
reducing properties nature of Barnes
metal e-type physical properties will
because flame correlation density
melting and boiling points it will also
discuss chemical balance for the
alkaline earth metals similar to what we
have done for alkali metals let's start
the electronic configuration so
electronic configuration is business and
s2 so you see the electronica name is
investor if you see this guy has
students to all these will have a list
electronic configuration barely a
magnesium calcium strontium barium
radium all has an s2 electronic
configurations so if you see although
most will have to be electrons take any
of these out emotions have electrons so
what emotion will have now I'll talk
about the ining in the atomic radius CPC
the atomic and ionic radius increase as
we go down the similar trend as we had
in alkali metals as we go down the route
number of shells increase the size in
case but if you compare the alkaline
earth metal with alkali metals you see
that the atomic in the ionic radius in
the alkaline earth metal is less than
alkali metal as we have discussed in the
periodic properties
in the properties in the periodic table
if you see this is the trend the moment
you go from right to left the atomic
radius increase right because if you are
going from that suppose left to right
now
so you are increasing atomic number that
means the charge on nuclear right but
you are maintaining the number of shells
that is same right increasing the number
of really which are going from let
suppose magnesium to or sodium to
magnesium you see this trend see they're
going in this trend match me so the
gospel is going in this trend you are
maintaining the number of shells but
you're increasing the charge on the
nucleus so the the nucleus has more
power to attract electrons so the atomic
size decrease action like this we have
discussed so does if you compare it
supposing this is my alkali metal and
this is alkaline earth metal why because
this is one this is if you compare so
the alkaline earth metal is generally
smaller in size then alpha limit hope
you understand the spin the size
decrease as we go from left to right
alkali metal is Group one alkaline is
good too so if you go from you want to
look in size will decrease why because
the number of the charge in the nucleus
increases the number of shells is same
so the people´s has more power to
attract electrons now we talk about the
hydration in calpads hydration therapy
we have discussed this in the alkaline
chapter where we say that any in a
natural substance then it attracts so
water molecule it becomes high-priced
hydrated right and the energy is
released when this thing happened
because the hydrated is more stable okay
so but now if you see the hydration in
that field we compare the alkaline earth
way to with alkali metals alkaline earth
metal has more wise because see
everything dependence like that well if
you see this is the size trend right
this is my alkali and this is alkaline
earth metal right a now you see the size
of alkaline earth metal is less than
alkaline
for a given period the size is less and
they told the size is less in the cars
more so in that case here after the size
is more and the power is more accurate
you can use files more hey this power is
more however smaller size is less so it
can attract water molecule on the board
then alkali metals so alkaline metals
form more hydrated salt than alkylene
right because alkaline has less size and
more power that is favorable hydration
what I need is more power and small size
so if you see if you compare the
alkaline earth metal with alkali metal
both things are favorable article ein
augment have more power less size then
I'll kill ya so they are they they form
100 so on right that's why you see the
compounds of alkaline earth metals are
more extensively hydrated than those of
alkali metals example mgcl2 cacld
it exists as an bcl-2 success - and CAC
energy system but NEC and cassia they
don't have hydrate salt only I think Li
H we saw it exist as hydrated salt
because the theme was small in size but
so even knowing they are big in sizes so
they don't form islets but now if you
want to see the trends of hydration in
the create itself
there you see it for the same trend
because if you see in the same group the
size will increase right you see the
size is increasing the the power to form
hydration will decrease
tell me the role that the power for my
vision depends on size inversely
proportional to size so the same trend
actually the same trend the alkaline
that in the alkaline earth metal also
that trend is same the power to form
hydration decrease on increase in size
or as we good on them this is what we
have solved the last napple also this is
cobalt chloride the gluing current the
minute is phytate that is you add water
this becomes you got 6s - as I told
hydration means water the moment the
word hydration comes think of water that
means any substance an hat
you add some water to it it add some
water molecule to that it can 6/10 one
any number of molecules of now we talked
about the oxidation steam so if you see
all this barely magnesium calcium they
have two extra electrons see if they
lose two electrons they'll become stable
correct so they want to stable they lose
two electron so mostly the oxidation
state is plus two because if they lose
two electrons they become stable all
right let's talk about the metallic
character so if you compare with alkali
and they are less metalic right the
other trend is this fashion wait for
Metallica - this is the trend this is my
alkali this is alkaline earth metal
right so if you go from this to this
alkali metals are morbidly so alkaline
earth metal are less metric than ugly
but if you see in the same group if you
go down if you go down it has the same
trend if you go down the metal it will
increase mainly collector increasing as
we go down down why because the atomic
size is increasing and these electrons
are more free to go they are more free
but this is in case of barium this
electron is tied to the nucleus because
the size right there is nucleus in the
electrons closer so controlled so this
electron is not that free to move out
but you see the calcium magnesium so
here the electrons are free to move out
so the bitly character increase as we go
down the group similar train as we had
in the alkali on in most of the case you
see the train will be similar across a
particular though we talk about the
hydration we talk about the ionization
enthalpy metalic height or size
everything you see if you go down the
group for this is for alkali this fall
coming the property will always be same
correct the trend is almost same if you
go down the row for alkali or alkaline
but if you compare alkaline your kind
reference because of this you move in
the particular video let's talk about
the reducing nature you can also if you
go down the group it will follow the
same trend as a first falling in
alkaline alkali metals the size
increases the size increases that means
it can oxidize easily so the reducing
nature also increases liquid on the
group but if you compare this with
alkali metal then they are weaker
reducing it in alkali because alkali is
this if you move down to the same period
the size decreases
alright example this is my so we go in
this direction sodium is bigger than
Magnuson right so magnesium is smaller
since magnet is smaller it will not lose
electron easily as compared to sodium
right so this will not oxidize itself
easily so it will be less reducing agent
then I hope you understand
let us talk about density here also
it'll have the same trend density also
if you see if you go down this row
absolutely the density will increase
actually you see that's increased but
since I told you that density is nothing
but mass by volume right so we can guess
a regular trend for mass also because
the atomic number is increasing atomic
mass is increasing we can guess a
regular trend for volume also because
the shells are increasing to the volume
will increase but we can't guess a
regular trend for mass by volume weight
this is something which we can't guess
so experiment it has been found that it
is increasing but there's a variation it
has decreased again decreased then again
it's already increasing so then say is
something which you actually need to be
experimental you need to have data to
find yes difficult to guess the pattern
of density in the same row if you talk
about periods size if you come back in
here
is there a so sodium size decreases so
you see the mansion is fallible Sonia
so the density is also magnesium has a
higher density and this is experimented
battery right normally alkali metals are
having higher density them or the
chemicals they told you can't sure
shorthand person saying density pattern
just by the logical explanation you need
to have a data density figures by
experiment I will see that the alkaline
earth metals are denser than alkali ions
these are more dense because see one
critical parameter the size and if you
see people from here to here
the atomic mass also increases so if you
see from going to a here to here from
let's suppose group quanta group to the
March is increasing and the volume is
decreasing so in that case for sure we
can say that density of alkali metal
alkaline metal will be less than alkali
metal for sure why because this is Maha
volume right so from going from sodium
to magnesium sodium magnesium right so
the mass is increasing mass mass was
infusing and volume is decreasing and
this is most mass per volume so you're
increasing the miraDry and decreasing
the divet or sure you can see that the
density of magnesium to be important
sorry let's talk about the melting and
boiling point so you bending in boiling
point the same possibility of learn for
alkali metals where we have seen the
crystal lattice enthalpy here also
you'll see the crystal lattice enthalpy
smaller size higher is the melting point
same pattern will apply here also the
moment you go down the blue the size
increase size increase that means size
increase would on the room that means
the in stable new stable lattice
right the table ladders table are this
means
if you go down the but if you compare
the alkali metals in the alkaline metals
this is my alkali and this is alkaline
earth metal so alkaline metal are
smaller in size smaller in size that
means more stable lettuce and that means
I will take point so we compare with
alkali metals alkaline earth metal have
higher boiling point anybody you got the
closed structure and stable lattice she
look trend also if you trend if you go
down the group the melting point boiling
by this you see let's talk about another
trend called flame color what is flame
current so as we have told that you know
alkaline rock metal we burn this metal
in the flames and then in the Bunsen
burner and you see the color of the
flame with that did you take the color
trend or we we tell the characteristic
of the metal so what happens is when you
pass some energy to these metals the
electron get excited but again if you
want to come back to the ground state so
it comes back to ground shake it makes
light of different wavelength
lights have different colors because
every or there is a pretty color so
these gives different colors the Bunsen
burner but they relieved in magnesium
they don't impart color when burned in
the Bunsen burner why because barely no
magnesium if you see the ionization and
is more if you go down the a nation
edges decreasing because the size is
increasing right this this needs more
energy this needs more energy which we
will get from see the energy which we
get from Bunsen burner is not sufficient
to excite the electrons of barely
memorization and that's why they don't
need one color the generally bad color
band pond in the Bunsen burner because
buzzes mana has a limitation air you can
impart only certain amount of heat and
that amount of heat is not sufficiently
to excite these
my mission will be lame but these are
sufficient to excite electrons here
because the size of calcium and
responding with bigger and myrational is
less right so they don't impart color
but other ones impart color see the
calcium in part the brick red color
strontium the crimson and the medium
green color the impart encouraged oh but
the first two they don't impart color
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