Nuclear Physics & Radioactivity
Virtual Practical Activity 2
Isotopes
Name............................................................................................................
Open up the Isotopes and Atomic Mass Simulation (from PhET) located under Lesson 1: Atoms, Isotopes and
Radioisotopes.
Open up the Symbol and Abundance in Nature boxes by selecting the green + sign on each.
The simulation will open with the smallest possible isotope showing, which is Hydrogen-1.
The symbol for the Hydrogen-1 isotope is shown, and its abundance in nature is 99.9885%. This means that this
isotope of Hydrogen is by far the most abundant.
The Mass Number is the number of .............................. and ............................... in the nucleus of any isotope.
Add a neutron from the bucket to the hydrogen-1 isotope.
Write down the name of the isotope produced .................................... and its abundance in nature ................ %.
Is this isotope stable or unstable? .............................................
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Knowlege of Atomic Mass is not required in the VCE Physics course there is no need to select ‘Atomic Mass (amu)’.
Select Helium, He, from the periodic table and create all possible isotopes by adding or taking away neutrons. This
will enable you to complete the table below. Note that 0% abundance in nature means that the isotope does not
exist.
Name of Isotope
Symbol
Abundance in Nature (%)
Stable or Unstable?
Symbol
Abundance in Nature (%)
Stable or Unstable?
Symbol
Abundance in Nature (%)
Stable or Unstable?
Symbol
Abundance in Nature (%)
Stable or Unstable?
Helium-2
Repeat this process for Carbon, Oxygen and Neon.
Name of Isotope
Carbon-12
Name of Isotope
Oxygen-16
Name of Isotope
Neon-20
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Select the Mix Isotopes tab.
Minimise the Average Atomic Mass box by clicking on the
red – sign (you don’t need to know about atomic mass).
Note that only stable isotopes of each element will be
shown in this view.
Select Silicon Si from the periodic table and you will be invited to make a mix of stable isotopes of silicon. The
Percentage Composition of your isotope mix will be automatically calculated and shown.
Then select ‘Nature’s mix of isotopes’ to see the reative abundance of isotopes of Silicon in the earth’s
crust and atmosphere.
Investigate the first 18 elements of the periodic table (Hydrogen to Argon) to answer the following.
List the elements which have only one stable isotope. ......................................................................................
.............................................................................................................................................................................
List the elements which have two stable isotopes. ...........................................................................................
............................................................................................................................................................................
List the elements which have three stable isotopes. .........................................................................................
............................................................................................................................................................................
List the element(s) which have four stable isotopes. .......................................................................................
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