Activity 8: Isotopes
Some of the particles in atoms can alter their number
without the type of element changing. They are electrons and neutrons, as we
will see below.
Think and reason
Atoms are
composed of protons and neutrons in the nucleus and electrons in the Shell
The parts of the atom
- What do you think would happen if we remove protons from or add protons to the nucleus? Would it still be the same element?
- What about if we alter the number of neutrons? Would the type of element change?
Vocabulary of the atom
Activity 9: Crossword. The
structure of atom.
In this crossword, you must look for words about the atom and his
structure. Go to the following link:
Activity 10: Quizlets about
the atom
Go to the following link and
practice the vocabulary about the atom.
Drag corresponding items
onto each other to make then disappear
Activity 11: Listening and
reading
It's simple, go to the link
and type what you hear
Activity 12: Isotopes and atomic
mass
Go
to the following link:
https://phet.colorado.edu/sims/html/isotopes-and-atomic-mass/latest/isotopes-and-atomic-mass_en.html
Part A: Exploration
Go to the ‘isotopes’
section of the simulation. Once inside, play around with the various tools for
a few minutes.
Were you able to
find….
·
How to add and remove neutrons
·
What adding neutrons does the atomic symbol and
molecular model
·
Figure out what abundance in nature means
·
...Discover which is heavier, a proton or a
neutron
·
...Explore some ideas about what makes an atom
stable or unstable
If not, try playing around
a bit more until you find all of these items.
Once you’ve found them all, move on to Part B.
Part B: Developing Theories
Part B cont.:
1.
What is the relationship between natural
abundance and stability?
2.
What is an isotope? Based on your interaction with
the simulation, what do you think this is describing? (Hint: look what it says
in the abundance in nature tab about isotopes)
Dating a Fossil:
As soon as a living organism dies, it stops taking in new carbon. The ratio
ofcarbon-12 to carbon-14 at the moment of death is the same as every other living
thing, but the carbon-14 decays and is not replaced. The carbon-14 decays with its
half-life of 5,700 years, while the amount of carbon-12 remains constant in the
sample.
By looking at the ratio
of carbon-12 tocarbon-14 in the sample and comparing it to the ratio in a
living organism, it is possible to determine the age of a formerly living thing
fairly precisely.
3.
Why does the amount of C-14 go down? Justify your
answer using the simulation.
Part C: Mixtures
Play around with the simulation
making sure you can do the following…
·
Add two different isotopes to the box
·
Use the slider tool to quickly add atoms to
the box
·
Change the percent composition at will
·
Make the average atomic mass go up or down intentionally
·
See nature’s mix
·
Find an element with more than 2 isotopes
Part D: Average Atomic Mass
Clear the box of all
atoms. Then add the following combinations of atoms and fill out the table.
* challenge problems
Part D cont.:
1.
Name two things that determine the average atomic
mass of an element.
2.
Look at the natural abundance for 3 different
elements and find their average atomic masses.
Element 1: Avg. Atomic Mass in Nature:
Element 2: Avg. Atomic Mass in Nature:
Element 3: Avg. Atomic Mass in Nature:
3.
Compare the values you just got for the average
atomic mass and look at the periodic table for those elements. What do you notice?
4.
Describe what is the number on the bottom of
each elemental symbol on the periodic table telling you?
5.
Take a look at Boron (B) on the periodic table.
Make a guess about which isotope of Boron is the most abundant. Justify your answer.
Did you know?
To calculate the total mass of the atom we need to add
the separate masses of protons, neutrons and electrons. However, the mass of
the electrons is around 1000 times less than the sum of the other two. Therefore,
its value hardly affects the total mass.
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