Atoms and Elements – Building Atoms Simulation Lab
Background Information:
Atoms are the smallest things that retain the properties of matter we can observe. Atoms are made of three subatomic
particles; protons, neutrons, and electrons.



Protons have a mass of ___________ amu and a charge of ___________.
Neutrons have a mass of ___________ amu and a charge of ___________.
Electrons have a mass of nearly___________ amu and a charge of ___________.
Question/Purpose:
Purpose: Students will be able to describe the structure and function of parts of atoms.

Compare the charge, location, and relative mass of protons, neutrons, and electrons.

Explain that the number of protons in an atom determines what element it is.

Identify the basic parts of an entry in the Periodic Table and get information from it.
Procedure:
Procedure Part 1:
 Open the internet browser and enter the address: http://phet.colorado.edu
 Click on “Simulations” and select “Chemistry” from the menu on the left.
 Open the “Build an Atom” Simulation and select “Run Now”. Be patient.
Procedure Part 2:
 Explore the simulations to become familiar with how to use the program.
 Practice adding protons, neutrons or electrons. Observe what happens in each of these
situations. To start over, click “reset”.
 Collect data by using the simulation.
Observations/Data:
Question
1. Click the three green “+” signs on the right hand side of the screen.
2.
Answer
Build the atom on the computer to check to find the data:
a.
Look at a Periodic Table and find Beryllium (Be)
b.
How many protons are in a neutral Beryllium atom?
b.
c.
How many neutrons are in a neutral Beryllium atom?
c.
d.
How many electrons are in a neutral Beryllium atom?
d.
e.
How many valence electrons (electrons on the outer shell) does
Beryllium have?
e.
Atoms and Elements – Building Atoms Simulation Lab
2.
3.
f.
What will happen to the charge if you remove the valence electrons?
Check and see.
f.
g.
What are charged atoms called?
g.
h.
Remove one neutron.
i.
What word appears in the nucleus when you remove a neutron?
i.
j.
What is an atom called when the number of neutrons changes? Hint:
look at glossary!
j.
k.
What is the new mass of Beryllium?
k.
l.
Look on the right hand side and write down what it says in the symbol
box. Tell what each number means.
l.
Click “Reset All,” and then click the three green “+” signs on the right hand
side of the screen.
Answer the following questions first. Then build the atom on the computer
to check.
a. Look at a Periodic Table and find Nitrogen (N). Hint: search for
“periodic table” in a search engine.
b.
How many protons are in a neutral Nitrogen atom?
b.
c.
How many neutrons are in a neutral Nitrogen atom?
c.
d.
How many electrons are in a neutral Nitrogen atom?
d.
e.
Build this atom and check that you have built Nitrogen.
e.
f.
How many valence electrons does Nitrogen have?
f.
g.
As a nonmetal, Nitrogen will gain electrons to have a full valence shell.
How many valence electrons will Nitrogen gain to have a full valence
shell? Add this number of electrons.
g.
h.
What is the charge of this Nitrogen ion now? Check and see.
h.
i.
Look on the right hand side and write down what it says in the symbol
box. Tell what each number means.
i.
Atoms and Elements – Building Atoms Simulation Lab
Extension: Complete the data table.
Protons
Neutrons
Electrons
Atomic
Number
Mass
Number
Charge
Element
4
8
0
Be
Full Symbol
4
4
4
5
5
6
1.
2.
3.
4.
5.
8
8
7
6.
7.
8.
9.
10.
8
4
11.
12.
13.
7
13
-3
14.
15.
16.
17.
18.
9
20
-1
19.
20.
With remaining class time, play a few games. What is your highest score?
_______________
Discussion/Conclusion:
Answer these questions on a separate sheet. (Mini-PACER)
1. How are the three subatomic particles we studied similar and how are they different?
2. What determines the type of atom? Give examples.
3. Describe the information about atoms that can be found on the periodic table.
Be
Atoms and Elements – Building Atoms Simulation Lab
Glossary
Word
Atom
atomic number
atomic mass
chemical symbol
electron
electron cloud
group
ion
isotope
mass number
metal
metalloid
neutron
non-metal
nucleus
period
periodic table
proton
quark
Subatomic particle
Valence electrons
Definition
The smallest component of an element having the physical and chemical
properties of the element.
The number of positive charges or protons in the nucleus of an atom of a given
element.
The atomic mass of a chemical element is the average mass of an atom.
Atomic Mass = Protons + Neutrons
An abbreviation or short representation of a chemical element; the symbols in
the periodic table.
An particle of atoms consisting of a charge of negative electricity; mass =
1/1,836 amu.
The group of electrons revolving around the nucleus of an atom; a cloudlike
group of electrons.
Elements forming one of the vertical columns of the periodic table.
A positively or negatively charged atom due to gain or loss of electrons.
One of two or more atoms having the same atomic number but different mass
numbers due to more or less neutrons. There are 275 isotopes of the 81 stable
elements.
The sum of the number of neutrons and protons in an atomic nucleus.
Any of a class of elementary substances, As gold, silver, or copper, all of which
are crystalline when solid and many of which are characterized by opacity,
ductility, conductivity, and a unique luster when freshly fractured.
An element that has both metallic and nonmetallic properties, as arsenic, silicon,
or boron.
An elementary particle having no charge, mass slightly greater than that of a
proton.
A chemical element (as boron, carbon, or nitrogen) that lacks the characteristics
of a metal and that is able to form anions, acidic oxides, acids, and stable
compounds with hydrogen.
The positively charged mass within an atom, composed of neutrons and protons,
and possessing most of the mass but occupying only a small fraction of the
volume of the atom.
A sequence of elements arranged in order of increasing atomic number and
forming one of the horizontal rows in the periodic table.
A tabular arrangement of the elements according to their atomic numbers so
that elements with similar properties are in the same column.
A stable, positively charged subatomic particle.
Basic component of particles. Any of a group of six elementary particles having
electric charges of a magnitude one-third or two-thirds that of the electron.
Particles that are smaller than an atom, including protons, neutrons and
electrons.
Electrons found on the outermost shell or orbital of an atom. These electrons
are available for atomic bonding.