Trends in Group - 17 Elements (part - 2) Video Lecture - NEET

hello friends this video on p-block part
41 is rock you by exam clear calm no
more fear from exam the mixed friend
will discuss is the ionization enthalpy
CI a-- nation and help is one amount of
energy required to pluck a link that
lion isaac you'll get plus charge but
these group seventeen elements is a good
seventeen elements as they told the
electronic configuration is ns-two
and p5 the outermost electron otto
michelle has 5 + 2 7 electrons they need
only one electron to attain what noble
gas configuration and everybody want to
attain stability we have told that
stability in life noble gases are stable
so these elements they want only one
electron only one electron to attain
noble gas configuration now they are
almost very near to attaining that noble
gas tape they'll not give electron so
easily but if it equals if you take
example of sodium sodium has one extra
electron so if you if so it gives one
electron sodium can easily edema late
the noble gas configuration so for
sodium it is okay to give electron
because for sodium it is a win-win
situation you give electron you become
level but for chlorine or fluorine or
any of these halogen elements they need
only one electron so for them they will
easily take one electron because the
moment they take on electron they can
become stable but they would not like to
give electron because if they give one
electron then they leave two electrons
to be stable that is harder to achieve
so they are not like to give electron
that means they are not like to lose
electrons thus the
energy is very high you see the value of
finite energy
it's one six eight zero kilo Joule per
mole it's a very high value and dilation
and when you decreased on the group why
because fluorine is small in size this
fluorine has as a good control on this
electron this chlorine nucleus has a
good control on this electron it will
not let this electron to cope thus a
very high energy is required to plug
this electron but you talk about iodine
since it is bigger in size this iodine
nucleus doesn't have much control over
this electron on the outermost shell so
I it is little easy to block this
electron out compared to the floor in
case
so in iodine the ionization energy will
be little less and if you see all the
values were positive that means energy
is required to plug electron okay why it
is required because yeah this chlorine
on this halogen family they have seven
electrons they don't want to lose
electrons because now they need only one
electron to attain the noble gas
configuration if they lose one electron
then they need two electrons to attain
the noble gas configuration and then
they don't want to do that correct so
that's why they have very high energy
enthalpy the second is why does the
ionization enthalpy value decrease down
the group because if we go down the
group the size of that I'm increased in
the case of fluorine fluorine nuclear
has a very strong hold on this electron
it won't let this electron go easy so
you need high energy to plug this
electron in case of iodine since the
size is bad this nucleus doesn't have
much control on this electron and you
can easily plug this electron oh
computer throwing case and thus it has
little lesser ionizing than that let's
see the trends in the electronegativity
electronegativity is what it is the
tendency of the atom to attract other
electron towards itself okay and as we
know that the group 17 elements their
electronic configuration
is to np5 and they need only one
electron to be stable to be stable now
since they need only one electron to be
stable
they'll have tendency to attract the
nearby electrons and thus they'll have
high value of electronegativity and the
fact is that fluorine has the highest
value of electronegativity in the entire
periodic table not only in this book in
the entire periodic table it has the
maximum value of electronegativity and
that is for please note fluorine has the
highest value of electronegativity in
the entire periodic table so for
fluorine is the most electronegative
element found till now and why they are
this halogen families have high
electronegativity because these
hamiltonfamily element then you'd only
one electron to be stable and thus they
have tendency to attract one electron
from the nearby atoms and thus they are
electronically the electronegativity
values goes down the value goes down as
we go down the group if you see it is
four than we can three point two then
three two point seven and then 2.0 why
just guess thing why why why the value
of electronegativity is decreasing as we
go down the group think something from
the atomic size perspective you'll get
the answer correct you're thinking the
correct line the moment you go down the
group the atomic size increase the
atomic size increase this nucleus
because this is the nucleus is
positively charged and this nucleus
actually attracts electron so the size
increase since the size increase the
nucleus is not able to attract external
elect
listen this nucleus is not able to
attract external electrons so easy
example in this case of iodine this is I
already these nucleus will not be able
to attract the external electron because
you see there are so many electrons here
shielding effect plus the distance
increase a lot of factors so this
nucleus there is not equal to hot
electrons so easily and does the
electronegativity there is a tendency to
attract electro electro negativity is
nothing but tendency to attract
electrons so this tendency to attract
electron decrease as we go down the the
next trend will discuss as the electron
gain enthalpy
what is this electron gain enthalpy is
nothing but the amount of energy
released or required to gain an electron
and in this case we have told you that
chlorine
I mean this group 17 the electronic
configuration is n s 2 and P 5 that
means they need only one electron to be
stable right now they will happily
accept one electron in fact they will
release energy to get electron why
because then become stable they'll get
they'll attain the noble gas state and
does if you see the electron beam
enthalpy in all these cases negative
values that means the energy is released
the energy is released when you get one
electron and please note it has the
maximum a very very high value of
electron gain energy for a given period
it will have a maximum value of electron
density because in a given period group
17 elements are the only one that needs
only one electron to attain the noble
gas configuration for example if you
talk about one group it states this
group
lithium boron
neon is stable anyway it has stable gas
configuration oxygen needs to electron
to be stable nitrogen needs three
electron to be stable carbon needs four
electron to be stable boron has three
extra electron be radium has two extra
electron Liam has one extra electron
right fluorine is only one extra it to
be stable so fluorine needs only one
electron to be stable that means it will
take one electron and emit energy thus
the ionized electron gaining Kalki is
negative value but if you talk about
lithium the electron gain in that we may
not be negative
why because lithium doesn't need a
electron for lithium actually the
ionization energy will be negative
because if it loses electron it becomes
stable so think everything from the
stability perspective everybody wants to
be stable everybody wants what we in the
noble gas configuration for neon if you
want to lose a okay take a neon for
example if you talk about a electron
gain that we will be highly positive
because New Orleans oil is stable if you
try to keep an electron to neon it won't
accept easily because it is it'll lose
its stability does you may have to
provide extra energy to from give an
electron to neon but to give a electron
to fluorine is very easy
Florie diesel flooring is badly looking
for electron right and does the electron
beam enthalpy is negative for all the
elements in the group 17 okay and they
are maximum negative value of electron
given that we just need one electron to
attain the noble gas configuration okay
and now this electron gain tell me the
value if you see is decreasing down the
group okay
but in this case it has it is less
valuable from here from chlorine it is
decreasing down the group you see just
ignore the fluorine case we'll discuss
the flowing days later from chlorine
bromine iodine the value is decreasing
down the group y si
the same thing the size it's chlorine
bromine and iodine iodine will not be
able to attract electrons so easily but
you talk about the cronies and the
science is sloped chlorine will be able
to attract electrons easily so chlorine
will a bit more energy so chlorine will
emit 349 kilojoules of energy iodine
will not be able to attract electrons so
easily but still it needs one electron
to attain stability so it will emit two
96 kilo Joule per mole of energy so does
if you see the value of the electron
beam enthalpy actually decreases down
the room now let us talk about the
flooring by the values less why the
fluorine size is less but still the
electron gain enthalpy is s that is
because of Intel electronic repulsion
see this fluorine size is very small
taurine one is to do is to to be storing
see we talked about the fluorine this is
my nucleus this is 1s2 2s2 nearly
suppose p5 orbital 1 2 3 5 it was it
since the size is small they have in
turn electronic repulsion this is very
small this is a huge repulsion going on
here itself now it because the p orbital
is very small and it has 5 electrons
thus it doesn't entertain the incoming
electrons so easily this is a repulsion
here itself this is a space country it
is like overcrowded family the family is
already overcrowded they don't want to
entertain a new people even if the new
people will bring stability to their
life think of that perfect perspective
this is very small in size there is
small in size and this ultra small size
of fluorine actually gives a special
behavior to fluorine right it will it
has very high electronegativity but it
will not know entertain
electrons the electron comes here
because of the in intra electronic inter
electronic vapors shifts in minus 2p
already small size of - thank you was it
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