Name:____________________________________________________Pd:______Date:______________
Build an Atom Pre-Lab
1. You build an atom that has 3 protons, 4 neutrons, and 3 electrons.
2. Draw a picture of how you would build your atom below:
3. Which element does this atom depict? How do you know?
4. What is the mass of this atom? How did you determine this?
5. What is the charge of this atom? How did you determine this?
You want to change your atom’s properties. Circle YES if a change will work or mark NO if a change will
not work.
6. If you want to change the type of element of your atom, you can either:
a. add a proton
YES or NO
b. add a neutron
YES or NO
c. add an electron
YES or NO
7. If you want to change the charge of your atom, you can either:
a. add a proton
YES or NO
b. add a neutron
YES or NO
c. add an electron
YES or NO
8. If you want to change the mass of your atom, you can either:
a. add a proton
YES or NO
b. add a neutron
YES or NO
c. add an electron
YES or NO
Name:_____________________________________________________Pd:______Date:______________
Build an Atom Simulation
Objectives:
 Draw models that show atoms or ions.

Use information about the number of protons, neutrons, and electrons to identify an element
and its position on the periodic table

Predict how changing the number of protons, neutrons, or electrons will change the element,
charge, and the mass of an atom.
Procedure:
1. Make sure that all of the boxes in the bottom right hand
corner are checked, like in the diagram to the right.
2. Explore the Build an Atom simulation for about five minutes.
a. What parts go in the center of the atom? What is this
part called?
b. Explore and write down three examples of atoms that have a stable nucleus (it will say
either “stable” or “unstable” near the nucleus) and include a drawing of just your nucleus.
Number of Particles
in your Nucleus:
Draw your Nucleus:
Element Name:
protons:_____
1.
neutrons: _____
protons: _____
2.
neutrons: _____
protons: _____
3.
neutrons: _____
3. Everything around us is made up of different elements. The air has oxygen (O) and nitrogen (N).
Plants and people have lots of carbon (C) and hydrogen (H). Explore until you discover which particle
(or particles) determines the name of the element you build. What did you discover?
4. Test your idea by identifying each of the four elements below:
a. Protons: 6 Neutrons: 6 Electrons: 6
Element:______________________________________
b. Protons: 7 Neutrons: 6 Electrons: 6
Element:______________________________________
c. Protons: 6 Neutrons: 7 Electrons: 6
Element: ______________________________________
d. Protons: 6 Neutrons: 6 Electrons: 7
Element: ______________________________________
e. Which particle identifies the element:
5. Make sure both the “Net Charge” and “Mass Number” tabs are open.
click
6. Explore until you discover what affects the charge of your atom.
a. What is a rule for making a neutral atom?
b. What is a rule for making a positive ion (an atom with a positive charge)?
c. What is a rule for making a negative ion (an atom with a negative charge)?
7. Show a neutral atom, a positive ion, and a negative ion. All of your examples should have a stable
nucleus.
Number of Particles:
Draw your Atom or Ion:
What is the Charge?
protons:_____
Neutral
neutrons: _____
electrons:_____
protons:_____
+ Ion
neutrons: _____
electrons:_____
protons:_____
- Ion
neutrons: _____
electrons:_____
8. Explore until you discover what affects the mass of your atom.
a. Which particles are heavy and which particles are light?
b. What is a rule for determining the mass of an atom?
9. Using all of your rules, fill in the table below. You can test your ideas with the simulation. If you have
new ideas, rewrite your rules.
Action
Add a
Proton
What Changes?

Element

Charge

Mass
How Does it Change?
Action
Remove
a
Neutron
Action
Add an
Electron
What Changes?

Element

Charge

Mass
What Changes?

Element

Charge

Mass
How Does it Change?
How Does it Change?
10. Challenges!
Draw a positive ion with a charge of +3:
Particles
Properties
protons:_____
element:_____
neutrons: _____
mass: _____
electrons:_____
charge:_____
Stable Nucleus:_____
Draw an ion with a mass of 8 and a charge of -2:
Particles
Properties
protons:_____
element:_____
neutrons: _____
mass: _____
electrons:_____
charge:_____
Stable Nucleus:_____