Isotopes

1. 1cm
What are isotopes?
Isotopes are variations of
chemical elements that
have the same number of
protons but different
numbers of neutrons.

2. 1cm
What are isotopes?
Isotopes are variations of
chemical elements that
have the same number of
protons but different
numbers of neutrons.
We identify isotopes based
on their mass, whereby the
sum of protons and
neutrons equals the mass of
the isotope.

3. 1cm
What are isotopes?
This carbon atom has a
mass of 12:
6 protons + 6 neutrons.

4. 1cm
What are isotopes?
This carbon atom has a
mass of 12:
6 protons + 6 neutrons.
The name of this isotope,
then, is
12
C:
C for carbon, 12 for its mass.
12
C

5. 1cm
What are isotopes?
Two other isotopes of carbon
exist in addition to
12
C. They
are:
12
C
6 protons
+ 6 neutrons

6. 1cm
What are isotopes?
Two other isotopes of carbon
exist in addition to
12
C. They
are:
12
C 13
C
6 protons
+ 6 neutrons
6 protons
+ 7 neutrons
and…

7. 1cm
What are isotopes?
Two other isotopes of carbon
exist in addition to
12
C. They
are:
12
C 13
C
14
C
6 protons
+ 6 neutrons
6 protons
+ 7 neutrons
6 protons
+ 8 neutrons

8. 1cm
What are isotopes?
12
C 13
C
14
C
6 protons
+ 6 neutrons
6 protons
+ 7 neutrons
6 protons
+ 8 neutrons Since isotopes have distinct
masses, we identify C isotopes in
our samples by measuring the mass
of the carbon atoms. We use an
instrument called an isotope ratio
mass spectrometer to make these
measurements.