CHEMISTRY 1
Atomic Properties Activity
Name: _____________________________
In today’s class you will be exploring some of the properties of various elements. These properties will
include: atomic symbols, atomic numbers, numbers of protons, numbers of electrons, number of
neutrons, mass numbers, net charges, and the stability of the isotopes. To do so, you will be using an
online applet created and available for free through the University of Colorado.
1. Go to the following website: https://phet.colorado.edu/sims/html/build-an-atom/latest/buildan-atom_en.html . You’ll see a screen that looks like this
2. Select the “Atom” option to open up the first section of the applet that you will use. You will
find a screen like this
3. On this page you will want to turn on a few options before you begin. Open the “Net Charge”
and “Mass Number” boxes on the right hand side, and select the “Stable/Unstable” option at
the bottom. Drag one proton to the center of the atom. After doing so your screen should look
like this:
4. From this screen you will be able to determine all of the information in regard to several
different atomic arrangements. You’ll find those arrangements beginning on the next page. Add
protons, neutrons, and electrons to the atoms by clicking and dragging the spheres from their
respective containers into the atoms. Remove them by dragging them from the atom into their
containers.
5. You can also switch between the “Orbits” view and “Cloud” view by toggling just above the
electrons bucket. You’ll need to do this several times throughout the activity.
6. When you’ve finished the activity beginning on the following page, click the home icon at the
bottom, then on the right side of the screen double click the “Game” image. There you will be
taken to a screen like this:
7. Choose the first option and follow the directions for the game. Once finished, raise your hand
and I will come over and record your score for that game. Then return to the screen above and
continue through all of the games. Each time you finish a game raise your hand and I will come
by to record your score. When you’ve finished with all 4 games you have finished the in-class
activity. The questions to answer in this packet are due Monday.
Questions to Answer
Make predictions based on the following information. Then use the atom model to check if your
predictions were correct.
Atomic structure: 3 protons, 3 neutrons, 4 electrons
Prediction
Actual
Atomic Number
Atomic Symbol
Net Charge
Mass Number
Stable/Unstable
Atomic structure: 2 protons, 2 neutrons, 1 electron
Prediction
Actual
Atomic Number
Atomic Symbol
Net Charge
Mass Number
Stable/Unstable
Atomic structure: 8 protons, 8 neutrons, 10 electrons
Prediction
Atomic Number
Atomic Symbol
Net Charge
Mass Number
Stable/Unstable
Actual
What is a rule for making a neutral atom?
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What is a rule for making a +ion?
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What is a rule for making a – ion?
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What is a rule for determining the mass of an atom?
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Using all of your rules, figure out what changes for each of these actions to an atom or ion. You can test
your ideas with the simulation. If you have new ideas, rewrite your rules.
Action
Add a
Proton
Action
Remove a
Neutron
Action
Remove
an
Electron
Action
Add an
Electron
What
Changes?
□ Element
□ Charge
□ Mass
What
Changes?
□ Element
□ Charge
□ Mass
What
Changes?
□ Element
□ Charge
□ Mass
What
Changes?
□ Element
□ Charge
□ Mass
How Does it Change?
How Does it Change?
How Does it Change?
How Does it Change?