Anomalous Properties of Second Period Elements Video Lecture | Chemistry Class 11 - NEET

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classification of elements part 24 is
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part 1 to part 33 now I understand the
anomalous property of second period
elements so it doesn't observe that the
first element in each moves we have is
groups we have right the first element
in this group differs from the other
element in the group they have some
different properties example if you see
my lithium held or something like this
Ethier sodium potassium rubidium cesium
these are my elements in Group one right
so lithium
unlike other group oh no or carry matter
and verily muscle draw this back over
here magnesium calcium strontium barium
like this so this is my group alkali
metal alkaline earth metal group so
lithium
unlike other alkali metal and beryllium
unlike other elfin emitter they form
compounds with covalent character and
other members if you see they all form
ionic compound if you see NaCl KCl all
are ionic but this guy lithium and
beryllium they form covalent character
come on and these other guys form ionic
compounds right the property is
different
and if you see the Leath even where Liam
the properties more similar with a
second element of following group
example lithium has properties similar
to my mission and if you draw a Mohr
group here right so if you draw a move
of infinite right here the way will be
draw my room it is going on a
linear gallium helium Hallie Mecca and
the manganese sorry the beryllium
as property similar to alimony that's
what they have seen this is all tidal so
let me draw like this
the iam alien balloon right we have
sodium my nature
alien column we have silicon nitrogen
phosphorus oxygen going sulphur right so
if you see that lithium has a property
similar to manganese beryllium is
probably similar to ammonium boron has
properties similar to silicon carbon
similar to phosphor a something like
this right and this sort of similarity
is called diagonally relationship in and
this happens only for the this is only
for the first period and second for the
second and third period in the second
second period and thirdly this has this
issues only second third period so this
from here onwards if you see the
properties are matching right lithium
initially I'll signal already matches
but lithium has property more similar to
magnesium then with soon right and this
is jelly due to very small size these
therefore second period and element
right a very small size and very charged
to radius ratio and they are very high
electronegativity and this is the reason
why this annually happens right although
one more reason why it happens is
because this guy elements in this period
second period right this guy's are
victimized in 2p orbitals but from third
period onwards they have three years 3p
and 3d all authority if you see the
electronic configurations also right so
you see that there more element there
more orbitals available that's why it
isn't that the combined they have
anomaly but this
annually and this animal is fall
diagonally relationship periodic so
we'll take some examples on our the
oxidation state and covalency of
aluminum in a L see L 2 O 5 + 2 same so
let's fight oxidation state first and
let's assume oxidation state is ex
oxidation state of aluminum is X so
write l maryam oxidation state x
chlorine is minus 1 water is zero
because it's a neutral molecule and the
whole oxidation state is total is was 2
so let me add this X for ammonium 1
aluminum plus 1 chlorine minus 1 plus 5
into water molecule zero total is plus 2
so if you solve this you get X is going
to lastly so the oxidation state of
aluminum is lasting so I'll write
oxidation state of any residue plus 3
please not oxidation state is something
which depends on the compound right so
it may vary
oxidation state of an Maryam is plus 3
let's talk about covalency
so if you see this guy L Moony M it is
attached to six molecules one chlorine
firing water right on top it has charged
you know that's all success but if you
see this aluminum is attached to five
sorry six five water molecules and mine
chlorine atom so the covalency will be
already will be six five four five hydro
water molecule one for curing this
covalency is nothing but Normandy
covalent bond has made so there's six
covalent bond so the coherency of
aluminium is six and the oxidation state
of every means plus T and you see both
are different so you can say that
oxidation and covalence you're valuing
in this particular case is not same
correct hope you understand this
oxidation state is something you just
assume it X and your exhalation of
chlorine and water and the overall
oxidation state of the whole look
compound with that you can find
oxidation see covalency is nothing but
the number of Bond it has made so again
just find the structure of this
particular compound and you can get the
number of 2001 has been mean get the
covalency thank you visit exam viacom to
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