In this video, we are going to write
isotopic symbol for isotopes.
Isotopic symbol is also known as isotope notation
or nuclear notation. Basically it
contains three types of information, the
symbol of the element, the atomic mass
and the atomic number. We can write it
out this way where X is the chemical
symbol, A is the atomic mass and we write
it at the top left and Z is the atomic
number and we write it on the bottom
left. Atomic mass is the larger number
that's in decimal place and atomic
number is a smaller whole number.Tthis
information you can find them in the
periodic table. In case you need a recap
on what's an isotope, it's basically one
element having different variants. They
all have the same number of protons but
they have different number of neutrons
and because of that they have the same
atomic number but different atomic mass.
Just a quick recap, atomic number
represents the number of protons
whereas atomic mass is the sum of number
of protons and number of neutrons, and that's
why isotopes have the same atomic number
but different atomic mass, it's because
of the difference in number of neutrons.
So, let's take fluorine for example. It
has a total of 17 isotopes. They range
from fluorine 14 all the way to fluorine
31. From these 17 isotopes the most
stable and abundantly found isotope is
fluorine 19. Let's start with the most
stable fluorine isotope, which is
fluorine 19. So 19 right here represents
the atomic mass for this specific
isotope and if we look up the
information for fluorine this is what we
can find.
9 is the atomic number, that's the small
whole number. F is the chemical symbol, so,
these are the three information that we
need to plug in to the isotopic symbol
and this is what we get. The important
point to note is the atomic mass of the
isotopic symbol must be written in whole
number
since this represents the mass of a
specific isotope, so, meaning to say you
should write 19 for fluorine 19's
atomic mass not 18.998 which is the atomic mass you can
find in a periodic table because that
mass represents the mass of the other
isotopes that are present for fluorine.
If we're writing the isotopic symbol for
fluorine 31 it will be this. We simply
change out the atomic mass, the chemical
symbol and the atomic number stays the
same.
Now, let's do this the other way around.
What if we get an isotopic symbol and
we're asked to find the following atomic
number. Well that's written on the bottom
left, right? So, that means that's 16. Atomic
mass, well that's the number that is
written on the top left corner, so, that
means it's 34. Number of proton, that's
the same as the atomic number, so, that
means it's also 16. The number of
electrons in an atom is the same as a
number of proton which is also the same
as atomic number so that's 16 as well.
Number of neutrons, remember that atomic
mass is the number of proton plus number
of neutron? Well if you plug in the
information you can solve for a number
of neutron and that's 18.
To recap, we write the chemical symbol
on the right and the atomic mass on the
top left and followed by the atomic
number on the bottom left. Atomic mass is
the larger number that is found in the
periodic table or it can be given by the
question. Keep in mind that that's the
total number of protons and neutrons and
also this number must be written in
whole number for isotopic symbol whereas
the atomic number, that's the smaller
whole number found in the periodic table.
That is also the number of protons. With
that we're done with isotopic symbol.
Hope the video helped you out somehow. Do
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