Isotopes of Hydrogen Video Lecture - JEE

okay we're talking about isotopes and
I'll start off with hydrogen as an
example hydrogen can exist in three
forms the first one we've talked about
we have a single proton in the nucleus
with an electron circling it or an
electron around it and this is what we
would call ordinary hydrogen there's
another form of hydrogen though and it's
called deuterium and it has a proton and
a neutron in the nucleus and a single
electron around it so you can imagine it
looking something like this and this is
called deuterium that's de ute are I un
or sometimes called heavy hydrogen and
that's a good name for it
because it really is heavy compared to
regular hydrogen because it has this
extra mass of the neutron it's
approximately twice as heavy as regular
hydrogen because the proton and the
neutron remember have approximately the
same mass the electron is really really
tiny compared to the other particles so
the electron doesn't contribute much to
the overall weight of the hydrogen atom
but adding this extra Neutron in there
essentially doubles its mass so it has
the heavy hydrogen has a mass number of
two although it still has an atomic
number of one chemically it still
behaves like ordinary hydrogen you could
bond it with oxygen for example and form
what's called heavy water so in other
words you could have an oxygen molecule
where you had an oxygen atom and two
hydrogen's but these hydrogen's here
could be heavy hydrogen's and you'd have
a different form of water that they call
heavy water that would actually be a
little bit heavier than regular water
because it has these extra neutrons
inside the hydrogen atoms and heavy
water isn't particularly dangerous
although it is used in the
with other radioactive elements which
are dangerous and then there's a third
form of hydrogen called tritium and
tritium has a proton and two neutrons in
the nucleus there's still a single
electron going around but now we have a
mass number of three and tritium is a
dangerous substance its radioactive I'll
make a note of that and we'll talk more
about this what this means later on but
but basically it means that nucleus can
break apart tritium is not going to last
forever in a given day it has a certain
probability of decaying and that's
breaking apart of the nucleus breaks up
and particles come flying out and energy
comes flying out and that's what why
it's called radioactive because this
radiation is actively emitted from it
and the radiation can be harmful it can
mess up can damage your cells it can
damage your DNA it can end up causing
cancer or other problems the the
deuterium is not radioactive so it's
what we would call stable it doesn't
decay into the radiation it just remains
stable but the tritium is radioactive if
you were to make some heavy heavy water
out of tritium in other words if you
were to take a an oxygen molecule and
instead of the hydrogen molecules here
if these two hydrogen's in your h2o were
in fact tritium molecules it's um it is
dangerous you wouldn't want to drink
that it can harm you or even you don't
even want to get it on you because it
can cause damage to you but you can make
water like this if you have some tritium
it will bond with oxygen to form a water
molecule all three of these forms of
hydrogen have very similar chemical
properties because they have the same
number of protons in the in the nucleus
and specifically the same number of
electrons around the outside of the
nucleus and it's really the electrons in
the arrangement of the
Tron's on the outside of the atom that
determine its interaction with other
atoms so because these all have a single
electron around the nucleus they all
behave chemically in similar ways and
they will interact with other atoms in
similar ways and these three forms of
hydrogen are called three isotopes of
hydrogen and that's the term to know an
isotope of an atom is just a form of
that atom and different isotopes have
different numbers of neutrons in the
nucleus